UI Tweak: update setting dashboard cards background color.

Bug: 29397123
Change-Id: Ie503fa6ae390db3c9e651d8b95e5c86f29bca46c
diff --git a/res/layout/dashboard_tile.xml b/res/layout/dashboard_tile.xml
index 7a0cfbb..1ec1730 100644
--- a/res/layout/dashboard_tile.xml
+++ b/res/layout/dashboard_tile.xml
@@ -19,11 +19,11 @@
     android:id="@+id/dashboard_tile"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
+    android:background="?android:attr/selectableItemBackground"
     android:gravity="center_vertical"
     android:minHeight="@dimen/dashboard_tile_minimum_height"
     android:clickable="true"
-    android:focusable="true"
-    android:background="@drawable/selectable_card">
+    android:focusable="true">
 
     <ImageView
         android:id="@android:id/icon"