Rename can_be_approved_by? to be more descriptive

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/96224



Merged-by: Pavel Shutsin <pshutsin@gitlab.com>
Approved-by: Kerri Miller <kerrizor@kerrizor.com>
Approved-by: Pavel Shutsin <pshutsin@gitlab.com>
Co-authored-by: David Kim <dkim@gitlab.com>