Remove duplicate layout mobile_network_settings_container_v2

- MobileNetworkActivity can use settings_base_layout.xml as layout.
- MobileNetworkActivity need to use Theme.Settings.Home because
it requests Window.FEATURE_NO_TITLE. Otherwise MobileNetworkActivity
will show title defined in xml first then change to new title.

Fixes: 123794771
Test: rebuild, manual
Change-Id: I39ae25b6d335437ffddb2f1562e7a0347db97108

src/com/android/settings/network/NetworkDashboardFragment.java

@@ -56,7 +56,7 @@ public class NetworkDashboardFragment extends DashboardFragment implements
 
     @Override
     protected int getPreferenceScreenResId() {
-        return R.xml.network_and_internet_v2;
+        return R.xml.network_and_internet;
     }
 
     @Override
@@ -141,7 +141,7 @@ public class NetworkDashboardFragment extends DashboardFragment implements
     }
 
     public static final BaseSearchIndexProvider SEARCH_INDEX_DATA_PROVIDER =
-            new BaseSearchIndexProvider(R.xml.network_and_internet_v2) {
+            new BaseSearchIndexProvider(R.xml.network_and_internet) {
 
                 @Override
                 public List<AbstractPreferenceController> createPreferenceControllers(Context