Merge branch...

Merge branch '488615-setting-auto-merge-using-the-api-fails-when-the-option-is-available-in-the-ui' into 'master' 

Resolve "Setting auto-merge using the API fails when the option is available in the UI"

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/166301



Merged-by: Gavin Hinfey <ghinfey@gitlab.com>
Approved-by: Gavin Hinfey <ghinfey@gitlab.com>
Reviewed-by: Patrick Bajao <ebajao@gitlab.com>
Co-authored-by: Marc Shaw <mshaw@gitlab.com>