Merge branch 'sh-fix-llm-ai-client-204-response' into 'master'

Fix LLM AI client not returning a HTTP response with 204 responses

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/172025



Merged-by: Gosia Ksionek <mksionek@gitlab.com>
Approved-by: Gosia Ksionek <mksionek@gitlab.com>
Approved-by: Dmytro Biryukov <dbiryukov@gitlab.com>
Reviewed-by: Madelein van Niekerk <mvanniekerk@gitlab.com>
Co-authored-by: Stan Hu <stanhu@gmail.com>