minor #51064 [Messenger] Remove deprecated StopWorkerOnSignalsListener (HypeMC)

This PR was merged into the 7.0 branch.

Discussion
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[Messenger] Remove deprecated `StopWorkerOnSignalsListener`

| Q             | A
| ------------- | ---
| Branch?       | 7.0
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Followup to #50997.

Commits
-------

4366044e98 [Messenger] Remove deprecated `StopWorkerOnSignalsListener`

Author: nicolas-grekas

Tests/Fixtures/long_receiver.php

@@ -17,7 +17,6 @@
 use Symfony\Component\Messenger\Bridge\Amqp\Transport\Connection;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\EventListener\DispatchPcntlSignalListener;
-use Symfony\Component\Messenger\EventListener\StopWorkerOnSignalsListener;
 use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Messenger\Transport\Serialization\Serializer;
 use Symfony\Component\Messenger\Worker;
@@ -33,7 +32,6 @@
 $connection = Connection::fromDsn(getenv('DSN'));
 $receiver = new AmqpReceiver($connection, $serializer);
 $eventDispatcher = new EventDispatcher();
-$eventDispatcher->addSubscriber(new StopWorkerOnSignalsListener());
 $eventDispatcher->addSubscriber(new DispatchPcntlSignalListener());
 
 $worker = new Worker(['the_receiver' => $receiver], new class() implements MessageBusInterface {
@@ -49,5 +47,7 @@ public function dispatch($envelope, array $stamps = []): Envelope
     }
 }, $eventDispatcher);
 
+pcntl_signal(15, fn () => $worker->stop());
+
 echo "Receiving messages...\n";
 $worker->run();