Block metered APNs when app is restricted.

When an app is restricted in the background, don't allow them to
start using metered network features. With this change they can
still use network features when in foreground. This avoids situation
where apps can bring up APNs which they are unable to use.

Bug: 5838267
Change-Id: I3ac96f2a545f67cba1ef12b8536cfd0da769d955