Remove the NotificationsLiveDataStoreRefactor flag

NotifLiveDataStore has been replaced by ActiveNotificationsInteractor,
and all remaining usages were migrated behing the NotifLiveDataStoreRefactor
flag.

Bug: 424001722
Test: smoke test the new NotificationLogger
Test: check lights out mode
Flag: EXEMPT mechanical refactor
Change-Id: Ia07ba4c7bccd1696bceb8e61d6f693971c356379