Filter out detached views from touch

Views that are detached shouldn't get touch events/start getting
animated (They can't be animated).

Added filter to stream to remove these views from consideration for the
nearest touch frame algo.

Test: Visually + unit test
Bug: 65146195
Change-Id: I74df495a7c02d3d46cd6784f0950c48b5311819e
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NearestTouchFrame.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NearestTouchFrame.java
index 1452e0c..e5083c1 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NearestTouchFrame.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NearestTouchFrame.java
@@ -95,8 +95,12 @@
     }
 
     private View findNearestChild(MotionEvent event) {
-        return mClickableChildren.stream().map(v -> new Pair<>(distance(v, event), v))
-                .min(Comparator.comparingInt(f -> f.first)).get().second;
+        return mClickableChildren
+                .stream()
+                .filter(v -> v.isAttachedToWindow())
+                .map(v -> new Pair<>(distance(v, event), v))
+                .min(Comparator.comparingInt(f -> f.first))
+                .get().second;
     }
 
     private int distance(View v, MotionEvent event) {