Implement new drag zone indicator regions.

Updates the drag zone indicators to Regions based on the task's pre-drag
windowing mode. Drag zone targets for freeform tasks have been updated
while other windowing modes remain the same.

Also, changes the coordinates fetched in handleCaptionThroughStatusBar
to raw x/y coordinates. This is due to each split stage having its own
coordinate space. Split left/right indicators from a drag from
splitscreen would not work properly otherwise.

Note these are visually inaccurate; transitions will be tied to these
regions in a future CL.

Bug: 280828642
Test: Manual
Change-Id: Ia58aae83e22d1576ef71172ce78323c0ae538b80