Merge branch '470053-policies-policy_group_scope-clean-up' into 'master'

Clean up policy_group_scope feature flag

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/165870



Merged-by: Alexander Turinske <aturinske@gitlab.com>
Approved-by: Alexander Turinske <aturinske@gitlab.com>
Reviewed-by: Alexander Turinske <aturinske@gitlab.com>
Reviewed-by: Artur Fedorov <afedorov@gitlab.com>
Co-authored-by: Artur Fedorov <afedorov@gitlab.com>