Merge changes I56648456,Ie4735471,Iad797def,I9521da3e,I3ed26200, ... into main

* changes:
  Start using ResolutionMechanism#isPolicyApplied
  Added tests for TopPriority#isPolicyApplied
  Added tests for StringSetIntersection#isPolicyAdded
  Added tests for MostRestrictive#isPolicyApplied()
  Added tests for MostRecent#isPolicyApplied()
  Replace kotlin 'assert' with Truth 'assertThat'
  Implement isPolicyApplied() in PackageSetUnion
  Implement method isPolicyApplied is FlagUnion
  Add default isPolicyApplied in ResolutionMechanism