Remove no-op handlePerferenceTreeClick from PrefControllers

Bug: 33429853
Test: RunSettingsRoboTests
Change-Id: I5633953e3d7b07f9006e541b96a24a2a769e2686

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

@@ -40,11 +40,6 @@ public class VpnPreferenceController extends PreferenceController {
         mIsSecondaryUser = !UserManager.get(context).isAdminUser();
     }
 
-    @Override
-    public boolean handlePreferenceTreeClick(Preference preference) {
-        return false;
-    }
-
     @Override
     public void displayPreference(PreferenceScreen screen) {
         super.displayPreference(screen);