Fix the overlap issue of MainSwitch and list view.

This issue happen on Developer and Wi-Fi pages, so the problem
should be solved on SettingsActivity.

Fix: 181341927
Test: Run robotest and see the ui
Change-Id: I57722cfcbeb6390c88101d808429346045e57c92

src/com/android/settings/SettingsActivity.java

@@ -309,6 +309,7 @@ public class SettingsActivity extends SettingsBaseActivity
         mMainSwitch = findViewById(R.id.switch_bar);
         if (mMainSwitch != null) {
             mMainSwitch.setMetricsTag(getMetricsTag());
+            mMainSwitch.setTranslationZ(findViewById(R.id.main_content).getTranslationZ() + 1);
         }
 
         // see if we should show Back/Next buttons