Only close overlays onTaskMovedToFront for desktop prototype.

Test: Overlays stay open when task moves to front when prototype
disabled.
Fix: 280483451

Change-Id: Iba345d30e6339e76fbdf19a33fde78e4441d6065

quickstep/src/com/android/launcher3/taskbar/overlay/TaskbarOverlayController.java

@@ -36,6 +36,7 @@ import com.android.launcher3.AbstractFloatingView;
 import com.android.launcher3.DeviceProfile;
 import com.android.launcher3.taskbar.TaskbarActivityContext;
 import com.android.launcher3.taskbar.TaskbarControllers;
+import com.android.quickstep.views.DesktopTaskView;
 import com.android.systemui.shared.system.TaskStackChangeListener;
 import com.android.systemui.shared.system.TaskStackChangeListeners;
 
@@ -65,7 +66,9 @@ public final class TaskbarOverlayController {
 
         @Override
         public void onTaskMovedToFront(int taskId) {
-            mProxyView.close(false);
+            if (DesktopTaskView.DESKTOP_MODE_SUPPORTED) {
+                mProxyView.close(false);
+            }
         }
     };