Prevent non-fullscreen activities from triggering auto-enter PiP

Bug: 63581685
Test: android.server.cts.ActivityManagerPinnedStackTests
Test: #testAppOpsDenyPipOnPause
Test: Launch screenshot from notification tray above auto-enter PiP
      activity

Change-Id: I0bddfd5c47d6053d079b9bd426003d526e8bb0dd
2 files changed