Fix backup and restore of package blocks

-Restore block status for apps that already exist
E.g. apps on the system image
- Stop depending on appops, it's duplicative and
not backuped/restored

Fixes: 38340377
Test: runtest systemui-notification, toast and notification
cts tests, backup android, clear data on packages, restore android,
verify that blocked apps stay blocked.
Change-Id: I29a33d7db2701bd64a7b30411dcf77c0a2f321d1