Following T387324: Add hook to support custom logging in `ProtectedVarsAccessLogger`, we should no longer be checking for CheckUser in ProtectedVarsAccessLogger and instead should use this new mechanism from within the CU extension instead. Since CU no longer needs to expose its log to other extensions, the changes made in I35d50df7cd6754e29d964cc716fb3c42406272df could possibly be removed as well.
Acceptance Criteria:
- ProtectedVarsAccessLogger no longer needs to check for CU or use its logger
- Any refactoring needed to be done to TemporaryAccountLogger (external logging) is done
- CheckUser calls the new hook in ProtectedVarsAccessLogger to log access
- Access is not logged twice between AbuseFilter and CheckUser (feature parity)