Changes to Lookup Generic Assets

removed the optional property additionalProperties/owner_subaccount_id from the response with the 200 status

added the optional property additionalProperties/members/items/open_datetime to the response with the 200 status

the additionalProperties/resolves_at/anyOf[subschema #1] response's property format changed from date-time to no format for status 200

added the optional property additionalProperties/members/items/event_subtitle to the response with the 200 status

endpoint added