minor #15423 [Configuration] Using MicroKernelTrait::getBundlesPath with Multiple Kernels (a-menshchikov)

This PR was merged into the 5.4 branch.

Discussion
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[Configuration] Using MicroKernelTrait::getBundlesPath with Multiple Kernels

See symfony/symfony#41566

Commits
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a69f6b3 MicroKernelTrait::getBundlesPath

Author: javiereguiluz

configuration/multiple_kernels.rst

@@ -91,15 +91,9 @@ files so they don't collide with the files from ``src/Kernel.php``::
     {
         use MicroKernelTrait;
 
-        public function registerBundles()
+        public function getProjectDir(): string
         {
-            // load only the bundles strictly needed for the API
-            $contents = require $this->getProjectDir().'/config/api_bundles.php';
-            foreach ($contents as $class => $envs) {
-                if ($envs[$this->environment] ?? $envs['all'] ?? false) {
-                    yield new $class();
-                }
-            }
+            return \dirname(__DIR__);
         }
 
         public function getCacheDir(): string
@@ -131,6 +125,12 @@ files so they don't collide with the files from ``src/Kernel.php``::
             $routes->import('../config/api/{routes}/*.yaml');
             // ... load only the config routes strictly needed for the API
         }
+
+        private function getBundlesPath(): string
+        {
+            // load only the bundles strictly needed for the API
+            return $this->getProjectDir().'/config/api_bundles.php';
+        }
     }
 
 Step 3) Define the Kernel Configuration