Use BubbleTaskViewListener for floating bubbles (behind a flag)

Flag: com.android.wm.shell.enable_bubble_task_view_listener
Test: manual - enable the flag and use floating bubbles, try basic
               interactions - expand, switch, dismiss, hit back
Bug: 272102927
Change-Id: Ide2298ce36c91eabb8603354ebe874a932ec1b82