Add non-transparent background to dashboard items.

Bug: 30297664

In previous CL I missed the background on this tile.

Change-Id: I87b1716dbcb0f79c6f7532f3ac2397feb3b4dfd0
diff --git a/res/layout/dashboard_tile.xml b/res/layout/dashboard_tile.xml
index 1ec1730..0e06d18 100644
--- a/res/layout/dashboard_tile.xml
+++ b/res/layout/dashboard_tile.xml
@@ -19,7 +19,7 @@
     android:id="@+id/dashboard_tile"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:background="?android:attr/selectableItemBackground"
+    android:background="@drawable/selectable_card"
     android:gravity="center_vertical"
     android:minHeight="@dimen/dashboard_tile_minimum_height"
     android:clickable="true"