Read permissions state from pm/Settings

adding ag/21644247 back (was reverted due to test failures)

Permissions are written to disk asynchronously,
when migrated in pm/Settings.java. New permission
subsystem should read it from settings instead of disk
during migration.


Bug: 266163862
Test: manual
Change-Id: I0373a82037f1cdcd9247a26ce729c9a8566f59f0