ElasticsearchClient.Indicies.GetAsync throws UnexpectedTransportException

[andersosthus]

Elastic.Clients.Elasticsearch version: 8.14.2

Elasticsearch version: 8.14.1

.NET runtime version: .net8 (8.0.7)

Operating system version: Ubuntu 20.04

Description of the problem including expected versus actual behavior:
When using ElasticsearchClient to load the Index settings it blows up when Dynamic Templates are defined

Steps to reproduce:

1. Create index with dynamic templates: curl -X PUT http://localhost:9200/testindex/ -H 'Content-Type: application/json' -d '{"mappings": {"dynamic_templates": [{"test": {"match_mapping_type": "boolean", "match": "*", "mapping": {"type": "boolean"}}}]}}'
2. Do a GetIndexRequest:

var client = new ElasticsearchClient(new Uri("http://localhost:9200"));
var indexReq = new GetIndexRequest("testindex");
var getResponse = await client.Indices.GetAsync(indexReq);

3. Observe exception thrown:

Elastic.Transport.UnexpectedTransportException: The JSON value could not be converted to System.Collections.Generic.ICollection`1[System.String]. Path: $ | LineNumber: 0 | BytePositionInLine: 3.
 ---> System.Text.Json.JsonException: The JSON value could not be converted to System.Collections.Generic.ICollection`1[System.String]. Path: $ | LineNumber: 0 | BytePositionInLine: 3.
   at System.Text.Json.ThrowHelper.ThrowJsonException_DeserializeUnableToConvertValue(Type propertyType)
   at System.Text.Json.Serialization.JsonCollectionConverter`2.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, TCollection& value)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   at System.Text.Json.JsonSerializer.Read[TValue](Utf8JsonReader& reader, JsonTypeInfo`1 jsonTypeInfo)
   at Elastic.Clients.Elasticsearch.Mapping.DynamicTemplateConverter.Read(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options) in /_/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DynamicTemplate.g.cs:line 120
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
   at System.Text.Json.Serialization.JsonDictionaryConverter`3.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, TDictionary& value)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
   at System.Text.Json.Serialization.JsonCollectionConverter`2.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, TCollection& value)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
   at System.Text.Json.Serialization.Metadata.JsonPropertyInfo`1.ReadJsonAndSetMember(Object obj, ReadStack& state, Utf8JsonReader& reader)
   at System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
   at System.Text.Json.Serialization.Metadata.JsonPropertyInfo`1.ReadJsonAndSetMember(Object obj, ReadStack& state, Utf8JsonReader& reader)
   at System.Text.Json.Serialization.Converters.ObjectDefaultConverter`1.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
   at System.Text.Json.Serialization.JsonDictionaryConverter`3.OnTryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, TDictionary& value)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   at System.Text.Json.JsonSerializer.Read[TValue](Utf8JsonReader& reader, JsonTypeInfo`1 jsonTypeInfo)
   at Elastic.Clients.Elasticsearch.Serialization.DictionaryResponseConverterFactory.ResolvableDictionaryResponseConverterInner`3.Read(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options) in /_/src/Elastic.Clients.Elasticsearch.Shared/Serialization/DictionaryResponseConverter.cs:line 78
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value, Boolean& isPopulatedValue)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.ContinueDeserialize(ReadBufferState& bufferState, JsonReaderState& jsonReaderState, ReadStack& readStack)
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.DeserializeAsync(Stream utf8Json, CancellationToken cancellationToken)
   at Elastic.Transport.DefaultResponseBuilder`1.SetBodyCoreAsync[TResponse](Boolean isAsync, ApiCallDetails details, RequestData requestData, Stream responseStream, String mimeType, CancellationToken cancellationToken)
   at Elastic.Transport.DefaultResponseBuilder`1.ToResponseAsync[TResponse](RequestData requestData, Exception ex, Nullable`1 statusCode, Dictionary`2 headers, Stream responseStream, String mimeType, Int64 contentLength, IReadOnlyDictionary`2 threadPoolStats, IReadOnlyDictionary`2 tcpStats, CancellationToken cancellationToken)
   at Elastic.Transport.HttpRequestInvoker.RequestCoreAsync[TResponse](Boolean isAsync, RequestData requestData, CancellationToken cancellationToken)
   at Elastic.Transport.DefaultRequestPipeline`1.CallProductEndpointCoreAsync[TResponse](Boolean isAsync, RequestData requestData, CancellationToken cancellationToken)
   at Elastic.Transport.DistributedTransport`1.RequestCoreAsync[TResponse](Boolean isAsync, HttpMethod method, String path, PostData data, RequestParameters requestParameters, OpenTelemetryData openTelemetryData, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at Elastic.Transport.DistributedTransport`1.ThrowUnexpectedTransportException[TResponse](Exception killerException, List`1 seenExceptions, RequestData requestData, TResponse response, RequestPipeline pipeline)
   at Elastic.Transport.DistributedTransport`1.RequestCoreAsync[TResponse](Boolean isAsync, HttpMethod method, String path, PostData data, RequestParameters requestParameters, OpenTelemetryData openTelemetryData, CancellationToken cancellationToken)
   at Elastic.Clients.Elasticsearch.ElasticsearchClient.<>c__DisplayClass28_0`3.<<DoRequestCoreAsync>g__SendRequest|0>d.MoveNext() in /_/src/Elastic.Clients.Elasticsearch/Client/ElasticsearchClient.cs:line 158
--- End of stack trace from previous location ---
   at Program.<Main>$(String[] args) in /home/anders/src/RandomStuff2/RandomStuff/Program.cs:line 9
   at Program.<Main>(String[] args)

Expected behavior
Everything works