Avoid unnecessary event subscribers

Refs #1578.

src/Extension/DefaultLanguagePackGuard.php

@@ -14,7 +14,6 @@ namespace Flarum\Extension;
 use Flarum\Extension\Event\Disabling;
 use Flarum\Http\Exception\ForbiddenException;
 use Flarum\Settings\SettingsRepositoryInterface;
-use Illuminate\Contracts\Events\Dispatcher;
 
 class DefaultLanguagePackGuard
 {
@@ -28,19 +27,7 @@ class DefaultLanguagePackGuard
         $this->settings = $settings;
     }
 
-    /**
-     * @param Dispatcher $events
-     */
-    public function subscribe(Dispatcher $events)
-    {
-        $events->listen(Disabling::class, [$this, 'whenExtensionWillBeDisabled']);
-    }
-
-    /**
-     * @param Disabling $event
-     * @throws ForbiddenException
-     */
-    public function whenExtensionWillBeDisabled(Disabling $event)
+    public function handle(Disabling $event)
     {
         if (! in_array('flarum-locale', $event->extension->extra)) {
             return;

src/Extension/ExtensionServiceProvider.php

@@ -11,6 +11,7 @@
 
 namespace Flarum\Extension;
 
+use Flarum\Extension\Event\Disabling;
 use Flarum\Foundation\AbstractServiceProvider;
 use Illuminate\Contracts\Container\Container;
 
@@ -38,8 +39,9 @@ class ExtensionServiceProvider extends AbstractServiceProvider
      */
     public function boot()
     {
-        $events = $this->app->make('events');
-
-        $events->subscribe(DefaultLanguagePackGuard::class);
+        $this->app->make('events')->listen(
+            Disabling::class,
+            DefaultLanguagePackGuard::class
+        );
     }
 }