[11.x] Fix an issue with missing controller class (#50505)

* Use file_exists for ControllerMakeCommand

* wip

src/Illuminate/Routing/Console/ControllerMakeCommand.php

@@ -127,7 +127,7 @@ protected function buildClass($name)
             $replace['abort(404);'] = '//';
         }
 
-        $baseControllerExists = class_exists($rootNamespace.'Http\Controllers\Controller');
+        $baseControllerExists = file_exists(app_path('Http/Controllers/Controller.php'));
 
         if ($baseControllerExists) {
             $replace["use {$controllerNamespace}\Controller;\n"] = '';