Update USER_SENSITIVE flags on app install and optimize it

This also parallelizes flag updating

Bug: 141311767
Test: - on first boot go to permissions screen, and ensure system apps
categorization makes sense
- install app that requests location, and ensure it's not listed
as system app in permission screen

Note: listener in PermissionPolicyService is currently disabled

Change-Id: I33977b70af0733852dc23e76c2b1bc4130825606