Followup fb087b7ff6d168bbfcaa5f83d53ac122d6a18a1c
post_links_allowed_groups is an odd check tied to
unrestricted_link_posting? in PostGuardian, in that
it doesn't have an escape hatch for staff like most
of the rest of these group based settings.
It doesn't make sense to exclude admins or mods from
posting links, so just always allow them to avoid confusion.
4ce1c2c030