Handle null case in AppStateAppOpsBridge

AppStateAppOpsBridge#getEntries returns null if no app
is requesting AppStateAppOpsBridge#mPermissions,
which would cause the settings app to crash in
AppStateAppOpsBridge#loadAllExtraInfo or
AppStateAppOpsBridge#loadAppOpsStates.

Try to skip null case here and set null for extraInfo
when we get null from AppStateAppOpsBridge#getEntries.

Change-Id: Iac03ec11869eeac62fa055da26b4b7a10dc65bb8
Fix: 147479269
Test: Open All files access and no crash.