Merge branch 'if-416281-omniauth_facebook_removal' into 'master'

Remove Facebook OmniAuth integration

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/151348



Merged-by: Aboobacker MK <akarakath@gitlab.com>
Approved-by: Harsha Muralidhar <hmuralidhar@gitlab.com>
Approved-by: Aboobacker MK <akarakath@gitlab.com>
Reviewed-by: Evan Read <eread@gitlab.com>
Co-authored-by: Imre Farkas <ifarkas@gitlab.com>