Patching null dereference in AbstractFloatingView.getOpenView()

If there is a better solution, bug assignee, please proceed with it.

I'll land this immediately, as a lot of tests are broken.

Bug: 130739123
Change-Id: Iacdb9adbbf41f1f9de1390c3e7525ee0bd7beda6

src/com/android/launcher3/AbstractFloatingView.java

@@ -182,6 +182,7 @@ public abstract class AbstractFloatingView extends LinearLayout implements Touch
     protected static <T extends AbstractFloatingView> T getOpenView(
             ActivityContext activity, @FloatingViewType int type) {
         BaseDragLayer dragLayer = activity.getDragLayer();
+        if (dragLayer == null) return null;
         // Iterate in reverse order. AbstractFloatingView is added later to the dragLayer,
         // and will be one of the last views.
         for (int i = dragLayer.getChildCount() - 1; i >= 0; i--) {