do not pass collection extensions to get_request_model

Author: hrodmn

stac_fastapi/pgstac/app.py

@@ -94,7 +94,7 @@
     collections_get_request_model = EmptyRequest
 
 post_request_model = create_post_request_model(extensions, base_model=PgstacSearch)
-get_request_model = create_get_request_model(extensions + collection_extensions)
+get_request_model = create_get_request_model(extensions)
 
 api = StacApi(
     settings=settings,