Update customize button title when state changed

- This CL update customize button title when
  onCustomizedButtonStateChanged() is called.
- Add test case

Bug: 152002708
Test: make -j42 RunSettingsRoboTests
Change-Id: I85c9cf90305757e279c058db2875e303b4add437

src/com/android/settings/panel/MediaOutputPanel.java

@@ -166,7 +166,7 @@ public class MediaOutputPanel implements PanelContent, LocalMediaManager.DeviceC
     }
 
     @Override
-    public CharSequence getCustomButtonTitle() {
+    public CharSequence getCustomizedButtonTitle() {
         return mContext.getText(R.string.media_output_panel_stop_casting_button);
     }