ApnSettingsActivity shows the ActionBar

- Use the Theme.Settings.NoActionBar
- Update test cases

Fixes: 331308440
Test: atest com.android.settings.UtilsTest SettingsActivityTest
Change-Id: Ica93e765690707654ae651261ac8d236ed8e1d58

tests/robotests/src/com/android/settings/SettingsActivityTest.java

@@ -27,6 +27,7 @@ import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import android.app.ActionBar;
 import android.app.ActivityManager;
 import android.content.Context;
 import android.content.Intent;
@@ -114,6 +115,15 @@ public class SettingsActivityTest {
         assertThat(((ListenerFragment) fragments.get(1)).mOnActivityResultCalled).isTrue();
     }
 
+    @Test
+    public void getActionBar_hasNoActionBar() {
+        final SettingsActivity activity = Robolectric.buildActivity(SettingsActivity.class).get();
+
+        final ActionBar actionBar = activity.getActionBar();
+
+        assertThat(actionBar).isNull();
+    }
+
     public static class ListenerFragment extends Fragment implements OnActivityResultListener {
 
         private boolean mOnActivityResultCalled;