Animate the expansion/collapse of a slice

Fixes: 123950127
Test: visual
Change-Id: If78bace71b166c484c8f4c358f1007bd2f6ffc89

res/layout/homepage_slice_tile.xml

@@ -31,6 +31,7 @@
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_gravity="center_vertical"
+            android:animateLayoutChanges="true"
             style="@style/SliceViewStyle"/>
 
         <!--dismissal view-->

src/com/android/settings/homepage/contextualcards/slices/SliceFullCardRendererHelper.java

@@ -16,6 +16,7 @@
 
 package com.android.settings.homepage.contextualcards.slices;
 
+import android.animation.LayoutTransition;
 import android.content.Context;
 import android.view.View;
 
@@ -94,6 +95,7 @@ class SliceFullCardRendererHelper implements SliceView.OnSliceActionListener {
         public SliceViewHolder(View view) {
             super(view);
             sliceView = view.findViewById(R.id.slice_view);
+            sliceView.getLayoutTransition().enableTransitionType(LayoutTransition.CHANGING);
         }
     }
 }