Implement expanded PiP on TV.

- Launch into expanded PiP
- Let user toggle expanded PiP in Menu
- Update moving the PiP via DPAD for expanded PiP
- Let app dynamically change the expanded PiP aspect ratio
- Let app dynamically change the PiP aspect ratio
- Let app dynamically enable/disable expanded PiP

Bug: 203647003
Test: atest PinnedStackTests#testEnterExpandedPipAspectRatio
Test: atest PinnedStackTests#testEnterExpandedPipAspectRatioMaxWidth
Test: atest PinnedStackTests#testEnterExpandedPipAspectRatioMaxHeight

Change-Id: Ie7de6a7fcc424b0c086fdae1f66aa8de42e53b0c