Fix indices.get_mapping API (#3977) (#3982)

(cherry picked from commit 311a18a)

Co-authored-by: Quentin Pradet <quentin.pradet@elastic.co>

Author: github-actions[bot]

output/openapi/elasticsearch-openapi.json

@@ -65,6 +65,7 @@ export enum RuntimeFieldType {
   date,
   double,
   geo_point,
+  geo_shape,
   ip,
   keyword,
   long,

output/openapi/elasticsearch-serverless-openapi.json

@@ -48,6 +48,7 @@ export class GeoShapeProperty extends DocValuesPropertyBase {
   coerce?: boolean
   ignore_malformed?: boolean
   ignore_z_value?: boolean
+  index?: boolean
   orientation?: GeoOrientation
   strategy?: GeoStrategy
   type: 'geo_shape'