Adjust TvPipMenuView.Listener interface wrt TvPipMenuModes

The tv pip menu modes allow to merge the onBackPress and
onExitMoveMenu callbacks into a single callback - onExitMenuMode.
This CL cleans up the menu mode exit path using the tv pip menu
modes.

The CL also simplifies the onPipMovement callback since the
TvPipMenuView already knows the menu mode.

Bug: 220108601
Test: atest TvPipMenuControllerTest
Change-Id: I9c26332a69ca2f1717662693a32403d0cd82b459