Previously, on sites that require staff to approve new members,
moderators were not reminded about people waiting for approval until 8
hours (480 minutes) after they registered, leaving new members waiting
far longer than necessary.
This change adds an `update_pending_users_reminder_default` upcoming
change that lowers the `pending_users_reminder_delay_minutes` default to
30 when enabled, so staff are notified promptly. It uses the virtual
default-override mechanism rather than writing to the DB, so an admin
who has customized the setting keeps their value and disabling the
change restores the previous default. The change is only surfaced on
sites with `must_approve_users` enabled, since the reminder never fires
otherwise.
2937da0e36
