Check for recents task info in cascading if running returns null

When launching into desktop following a restart, all existing tasks are
in recents and not running yet. Currently cascading only checks for
running taskInfo so no cascading is applied. Updated cascading to check
for recents taskInfo if not running taskInfo is found.

Flag: com.android.window.flags.enable_cascading_windows
Test: atest WMShellUnitTests:DesktopTasksControllerTest
Bug: 408092956

Change-Id: Id105ec21f87e1b63ec9cc24909119e87fd06571e