Use desktop API to remove desktop for dismiss

When overview tile for desktop is dismissed, use the shell API instead
of calling the system server directly to remove tasks in the desktop.
This let's desktop fix it's state and call the system server instead.

Bug: 370757235
Test: m and dismiss overview tile from desktop
Flag: com.android.window.flags.enable_desktop_windowing_back_navigation

Change-Id: Ia2abd0ab5a27759c92e0328beb460810ad2af898