Made popupContainer's shadow & arrow visible in secondary display

Reduced elevation of app drawer to 0dp because it was conflicting with popup container elevation

Test: Manual
Change-Id: I222866ddfc44ebf9ecd9787bb448e502339a1688
Fix: 233932585
(cherry picked from commit 354fe14cd4)

res/layout/secondary_launcher.xml

@@ -18,6 +18,7 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:id="@+id/drag_layer"
+    android:clipChildren="false"
     android:padding="@dimen/dynamic_grid_edge_margin">
 
     <GridView
@@ -52,7 +53,6 @@
         android:saveEnabled="false"
         android:layout_gravity="bottom|end"
         android:background="@drawable/round_rect_primary"
-        android:elevation="2dp"
         android:visibility="invisible" >
 
         <include