Implement method isPolicyApplied is FlagUnion

The isPolicyApplied method checks whether all the set bits int the given
policy value are also set in the resolved value.

Bug: 285532044

Test: atest com.android.server.devicePolicy.ResolutionMechanismTest#isPolicyApplied_flagUnion_flagSet_returnTrue
Test: atest com.android.server.devicePolicy.ResolutionMechanismTest#isPolicyApplied_flagUnion_flagNotSet_returnFalse
Test: atest com.android.server.devicePolicy.ResolutionMechanismTest#isPolicyApplied_flagUnion_someFlagsNotSet_returnFalse

Flag: TEST_ONLY

Change-Id: Id914a3f91be0e255550fb9b4a34092e8e15df127