Add "query_response_hit_ids" to query.request schema

[epugh]

Currently, behind the covers, the OS UBI plugin tracks when you make a query request all the document id's that have been matched for the query that will be sent to the user. We store this like:

This is from the OpenSearch ubi_queries index!

However, when we wrote the pure JavaScript client, ubi.js, we did not implement that because those two fields are not in the query.request.schema.json. Indeed, it tracks slightly different:

Also from OpenSearch ubi_queries index.

So, one more wrinkle. Our mappings and demo dashboards all use "query_response_hit_ids" instead of "query_response_object_ids", as it's highlighting these are hits from the query. To get things aligned, we are going to use that terminology everywhere.

This would an optional property....