Remove redundant codes and optimize comments.

Author: owent

exporters/otlp/include/opentelemetry/exporters/otlp/otlp_grpc_client_options.h

@@ -94,8 +94,8 @@ struct OtlpGrpcClientOptions
 
   /**
    * Optional caller-provided gRPC channel arguments.
-   * This is a non-owning pointer, and the pointed-to arguments are copied when the channel is
-   * created.
+   * This is a non-owning pointer. If set, the pointed-to object must remain valid
+   * until the gRPC exporter or client has been constructed.
    */
   const grpc::ChannelArguments *channel_arguments{};
 };

exporters/otlp/src/otlp_grpc_client.cc

@@ -398,8 +398,6 @@ std::shared_ptr<grpc::Channel> OtlpGrpcClient::MakeChannel(const OtlpGrpcClientO
 void OtlpGrpcClient::PopulateChannelArguments(const OtlpGrpcClientOptions &options,
                                               grpc::ChannelArguments &grpc_arguments)
 {
-  grpc_arguments = grpc::ChannelArguments{};
-
   if (options.channel_arguments != nullptr)
   {
     grpc_arguments = *options.channel_arguments;