Merge branch 'pass-anthropic-parameters-to-v1-chat-agent-endpoint' into 'master'

Pass Anthropic parameters to AI Gateway

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/139499



Merged-by: Alexandru Croitor <acroitor@gitlab.com>
Approved-by: Gosia Ksionek <mksionek@gitlab.com>
Approved-by: Alexandru Croitor <acroitor@gitlab.com>
Co-authored-by: Shinya Maeda <shinya@gitlab.com>