Merge branch '6.3' into 6.4

* 6.3:
  [Process] Fix test case
  [Workflow] fix MermaidDumper when place contains special char
  [Crawler] Fix regression where cdata nodes will return empty string
  [DoctrineBridge] Bugfix - Allow to remove LazyLoaded listeners by object
  [Messenger] Add forward compatibily with php-amqp v2

Author: nicolas-grekas

Transport/Connection.php

@@ -435,7 +435,7 @@ public function get(string $queueName): ?\AMQPEnvelope
 
     public function ack(\AMQPEnvelope $message, string $queueName): bool
     {
-        return $this->queue($queueName)->ack($message->getDeliveryTag());
+        return $this->queue($queueName)->ack($message->getDeliveryTag()) ?? true;
     }
 
     public function nack(\AMQPEnvelope $message, string $queueName, int $flags = \AMQP_NOPARAM): bool