Override desktop tasks corner radius during recents transition

Set the corner radius of desktop task surfaces to 0 during recents
transitions so that corner radius doesn't interfere with the surface
bounds and corner radius applied to the RemoteAnimationTarget leashes.

Bug: 378657004
Test: manual
Flag: com.android.window.flags.enable_desktop_recents_transitions_corners_bugfix

Change-Id: Ia653ace883cabfcd573ac138cb22affd96f7f229