fix(eval): Support include_intermediate_responses_in_final in final_response_match_v2

Expose the include_intermediate_responses_in_final setting in final_response_match_v2 and extract text from intermediate responses if enabled, ensuring intermediate text is formatted into the rater prompt correctly.

Closes #5695

Change-Id: Iecf5e9ff77a7e140fd3e4cf4abf7f8c595d7e58f