Bugfix: request()->user() in displayInNavigation is null (#105)

Bugfix for issue #104. 
Allow the use of policy in displayInNavigation by deferring display check to render time when currently logged in user is available.

Author: h-collector

src/Arbitrator.php

@@ -123,11 +123,11 @@ public function findOrFail(string $key): Resource
      */
     private function registerMenu(Resource $resource, int $key): Arbitrator
     {
-        if (! $resource::displayInNavigation()) {
-            return $this;
-        }
-
         View::composer('platform::dashboard', function () use ($resource, $key) {
+            if (! $resource::displayInNavigation()) {
+                return;
+            }
+
             $title = Menu::make()
                 ->canSee($key === 0)
                 ->title(__('Resources'))