Fixed the group appear animation for messaging

Messaging notification weren't appearing properly.

Change-Id: I63724319b7cab87ff3d33df03f5959c2437da9f6
Fixes: 63708826
Test: manual, add messaging group

packages/SystemUI/src/com/android/systemui/statusbar/notification/MessagingLayoutTransformState.java

@@ -383,6 +383,12 @@ public class MessagingLayoutTransformState extends TransformState {
         }
     }
 
+    @Override
+    public void prepareFadeIn() {
+        super.prepareFadeIn();
+        setVisible(true /* visible */, false /* force */);
+    }
+
     private void resetTransformedView(View child) {
         TransformState ownState = TransformState.createFrom(child, mTransformInfo);
         ownState.resetTransformedView();