Alternative fix for preventing PiP from screenshot sharing.

- Revert 942a85c6
- Use a more specific fix for the triggering of PiP from the SysUI
  screenshot share intent.

Bug: 63984385
Bug: 63581685
Test: android.server.cts.ActivityManagerPinnedStackTests
Test: Click share on the screenshot action, ensure activity below does
      not enter PiP
Change-Id: Id8041d50dd429030c20940dca19e5c62bbc0c6a4