Increase visibility of PhabricatorController::buildApplicationMenu methods

Summary: Ref T6822. This method needs to be `public` because it is called from `PhabricatorApplicationSearchController::buildApplicationMenu()`.

Test Plan: I wouldn't expect //increasing// method visibility to break anything.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6822

Differential Revision: https://secure.phabricator.com/D11416

src/applications/base/controller/PhabricatorController.php

@@ -425,7 +425,7 @@ abstract class PhabricatorController extends AphrontController {
       array_filter($phids));
   }
 
-  protected function buildApplicationMenu() {
+  public function buildApplicationMenu() {
     return null;
   }