Disable APN settings preference when DPC APNs are enforced

- As MobileNetworkSettings are ~10 dependent classes is not using support library, created a RestrictedPreference in com.android.phone similar to com.android.phone.RestrictedSwitchPreference

Bug: 72484718
Test: In TestDPC, enable override APN, APN setting preference is disabled. Switch to test DPC, disable override APN, APN setting preference is enabled.
Change-Id: I9c2e1e53106051a07e2f83ba20b7bc579bd12821
6 files changed