Filter out touches in the bottom area

When in edit mode, we want to filter touches on the bottom of the
ComposeView, so the shade can handle them (to collapse). This allows the
container in QSFragmentCompose to determine if a touch is inside the
bottom reserved space and if so, it ignores it (so the shade can handle
it).

Test: manual, both orientation, both types of navigation
Fixes: 412812554
Flag: com.android.systemui.qs_ui_refactor_compose_fragment
Change-Id: I927bd189f2a7c0ff54270a6419d0f8635ac7d258