Remove menu container's focus to avoid feedback background

Menu container contains no icons but holds a few buttons that may appear
later but using a mouse a square background will appear because it has
focus. Remove the focus to remove the feedback background ripple.

Test: use mouse and tap the area right of the home button
Change-Id: If4e57c1a27ca7fbe38712dc1ac6f9e5d2bb76c49
Fixes: 110042464

packages/SystemUI/res/layout/contextual.xml

@@ -20,6 +20,7 @@
              android:layout_width="@dimen/navigation_key_width"
              android:layout_height="match_parent"
              android:importantForAccessibility="no"
+             android:focusable="false"
              android:clipChildren="false"
              android:clipToPadding="false"
              >