Fix bottom zone is transparent in add network page

Override clipToPadding and clipToChildren attributes
to prevent view from overlapping problem.

Change-Id: I3493d80d89950545ea74b76e25c6f55069f83f5e
Fix: 145332638
Test: visual

res/layout/wifi_add_network_view.xml

@@ -19,6 +19,8 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
+    android:clipToPadding="true"
+    android:clipChildren="true"
     android:orientation="vertical">
 
         <include