TV Pip fixes after menu migration to Window

Moving TV Pip menu from an Activity to a Window caused NPE in
TvPipMenuController when referencing PipMenuView. This change fixes the
NPE as well as does initial refactoring in TV Pip implementation, such
as removing .tv.PipController.Listener and
.tv.PipContoller.suspend(resume)PipResizing methods.

Bug: 174818743
Bug: 171956642
Test: atest WMShellFlickerTests:TvPipBasicTest
Change-Id: Ifcd6c777a561421b45703300e3eccb44c13e2172