Register APPS_ALLOWED_ON_RESTRICTED_NETWORKS setting observer

PermissionMonitor register APPS_ALLOWED_ON_RESTRICTED_NETWORKS
setting observer to listen setting changed callback. Then update
or revoke permission for those apps.

Bug: 185149952
Test: atest FrameworksNetTests
Merged-In: I4b6a21bd3f47b7bcaac36fcabf1202a5a84a4520
(clean cherry-pick)

Change-Id: I4b6a21bd3f47b7bcaac36fcabf1202a5a84a4520