Backport 2345 to 8.11 (#2346)

* Add sparse vector property (#2345)

* Add SparseVectorProperty to Property union

* make contrib

* Add output/openapi/elasticsearch-serverless-openapi.json to .gitattributes

(cherry picked from commit 45873c6)

* Remove openapi output from 8.11 gitattributes

Author: Anaethelion

output/schema/schema.json

@@ -48,6 +48,7 @@ import {
   ScaledFloatNumberProperty,
   SearchAsYouTypeProperty,
   ShortNumberProperty,
+  SparseVectorProperty,
   TextProperty,
   UnsignedLongNumberProperty,
   VersionProperty,
@@ -117,6 +118,7 @@ export type Property =
   // complex
   | AggregateMetricDoubleProperty
   | DenseVectorProperty
+  | SparseVectorProperty
   | FlattenedProperty
   | NestedProperty
   | ObjectProperty