[PiP on CD] Add multidisplay handling for PiP input.

Bug: 390280408
Bug: 113087003
Test: Manually check that PiP on external display is consuming input on
PiP menu and dragging on PiP window is WAI
Test: atest PipResizeGestureHandlerTest PipTouchHandlerTest
Flag: com.android.window.flags.enable_connected_displays_pip

Change-Id: I036e817ef847f53c1af08894fa12615d3f760204