Custom JsonConverter is not honored when serializing script parameters.

[prochnowc]

NEST/Elasticsearch.Net version: 7.9.0

Elasticsearch version: 7.9.1

Description of the problem including expected versus actual behavior:

I have a custom JsonConverter registered to serialize Guid types using the shorter "N" format. To register custom
serializer I followed the guide at https://www.elastic.co/guide/en/elasticsearch/client/net-api/current/custom-serialization.html.

So far my custom converter works fine for document types, but as soon as I start to add complex script parameters which have Guid's inside my custom converter is not used anymore.

Expected behavior

Expected behavior is that a custom JsonConverter is used for document types and script parameters.

[russcam]

Relates: #4971

Closing this issue to consolidate discussion on the existing issue. @prochnowc please feel free to upvote the existing issue and discuss there.