Pass a location when dragging bubble to fullscreen

When a bubble is dragged to full screen, pass the x and y coordinates
of where the bubble was released to wm shell. The coordinates are used
as a starting point for expanding the full screen task.

Flag: com.android.wm.shell.enable_bubble_to_fullscreen
Bug: 388858013
Test: treehugger
Change-Id: I28bb10bdfb00786e43b350239cfdeb3df20b4a6f