[FEATURE]: Strip trailing role=assistant && content=="" messages before request #26320

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Before making a request, automatically strip any trailing messages in the message[] array where role=assistant and content == "".

Reason: These empty assistant messages are useless and possibly left over from message list generation/processing. Stripping them will reduce invalid tokens sent and make the process neater and more robust.

Proposed implementation:

• Before making a request (such as to an LLM/conversation service), iterate message[] backwards and remove all consecutive trailing messages matching the condition.

Reference code location: See packages/sdk/js/src/gen/client/client.gen.ts (beforeRequest), likely in the request pre-processing logic.