Handle recents transition using DefaultTransitionHandler when Desktop

Mode Active

When we are in desktop mode, we need to apply changes to the task surface such as setting the corner radius. To do so, we delegate recent transitions to the default mixed handler. After adding the required changes for desktop mode, RecentsTransitionHandler#startAnimation is applied.

Test: Open 2 tasks and swipe up to get the task bar. Corners should
remain rounded for all windows.
Bug: 280819685

Change-Id: Ic25047473780801531a64e205bea26fb0c1f4b79