Merge branch '428866-drop-index-users-for-authors' into 'master'

Drop index_users_for_auditors for .com

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/138110



Merged-by: Adam Hegyi <ahegyi@gitlab.com>
Approved-by: Adam Hegyi <ahegyi@gitlab.com>
Co-authored-by: Jon Jenkins <jjenkins@gitlab.com>