Merge branch 'block-seat-overages-allow-adding-members-already-in-group' into 'master'

Allow Adding Members Already in Group When Using Block Seat Overages

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/146429



Merged-by: Doug Stull <dstull@gitlab.com>
Approved-by: Doug Stull <dstull@gitlab.com>
Reviewed-by: Doug Stull <dstull@gitlab.com>
Reviewed-by: Vijay Hawoldar <vhawoldar@gitlab.com>
Co-authored-by: Jason Goodman <jgoodman@gitlab.com>