Update policy check from `authorize_admin_group` to
`authorize_admin_group_member`, in order to match API -
https://gitlab.com/gitlab-org/gitlab/-/blob/cb26a88c1852289bb19b11a8231610e0c2c72a49/ee/lib/ee/api/members.rb#L69.

https://gitlab.com/gitlab-org/gitlab/-/issues/262877