Add RTL support to communal touch handler.

This changelist adds RTL support for communal touch handler by adjusting
the touch initiation region based on the layout direction.

Test: atest CommunalTouchHandlerTest#testTouchInitiationArea
Bug: 320786721
Flag: com.android.systemui.communal_hub
Change-Id: Ib74758b3b1adec0a84f3a3596af76733f3cd967e