Merge branch '427095-make-index-not-unique' into 'master'

Drop unique constrain from index

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/137801



Merged-by: Adam Hegyi <ahegyi@gitlab.com>
Approved-by: Adam Hegyi <ahegyi@gitlab.com>
Co-authored-by: Tetiana Chupryna <tchupryna@gitlab.com>