[2/3] Use DragToBubbleController to show shell drags bubble drop targets

Updated logic to use DragToBubbleController to show drop target views
when launcher icon is being dragged over the bubble bar drop zones

Bug: 411505605
Flag: com.android.wm.shell.enable_create_any_bubble
Test: DragAndDropControllerTest
Test: Manual.
- Set gesture navigation mode
- Go to the application
- Drag icon from the taskbar towards the bubble bar drop zone
- Observe expanded view drop target appears fades in
- Drop icon to the bubble bar drop target, so app bubble is created
- Drag another icon from the taskbar towards bubble bar drop zone on the
opposite side
- Observe bubble bar is animated to that side
- Drop icon to the opposite side
- Observe second app icon is created
- Drag bubble bar to the dismiss target and perform the same test for
the 3 buttons navigation mode

Change-Id: I9e15492b1dc1708768003068c8dbe9af41721761