Remove sysui from having to manually notify pip visibility

- Set directly from the system when we enter/leave pip so there's
  no chance this gets out of sync

Bug: 167682726
Test: adb shell input keyevent 171 (ensures this still triggers the menu)

Change-Id: I73b4c5b6faebd505bf8e17b4c817b4d600025894
5 files changed