fix(tests): add missing RPC messenger handler for Symfony 8.1 compatibility

Symfony 8.1 Messenger strictly enforces `allow_no_handlers: false` (the default),
throwing NoHandlerForMessageException when dispatching a message with no handler.
The RPC entity uses `messenger: true` but had no handler registered.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: soyuka

tests/Fixtures/TestBundle/MessengerHandler/Entity/RPCHandler.php

@@ -0,0 +1,25 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\Fixtures\TestBundle\MessengerHandler\Entity;
+
+use ApiPlatform\Tests\Fixtures\TestBundle\Entity\RPC;
+use Symfony\Component\Messenger\Attribute\AsMessageHandler;
+
+#[AsMessageHandler]
+class RPCHandler
+{
+    public function __invoke(RPC $data): void
+    {
+    }
+}

tests/Fixtures/app/config/config_common.yml

@@ -371,6 +371,11 @@ services:
         tags:
             - name: 'messenger.message_handler'
 
+    app.messenger_handler.rpc:
+        class: 'ApiPlatform\Tests\Fixtures\TestBundle\MessengerHandler\Entity\RPCHandler'
+        tags:
+            - name: 'messenger.message_handler'
+
     ApiPlatform\Tests\Fixtures\TestBundle\Metadata\ProviderResourceMetadatatCollectionFactory:
         class: 'ApiPlatform\Tests\Fixtures\TestBundle\Metadata\ProviderResourceMetadatatCollectionFactory'
         decorates: api_platform.metadata.resource.metadata_collection_factory