Changes to Get chat messages

added the optional property error/misalignment/review_target to the response with the 400 status

added the optional property error/misalignment/review_target to the response with the 404 status

added the optional property error/misalignment/review_target to the response with the 429 status

added the optional property error/misalignment/review_target to the response with the 500 status

endpoint added