Merge branch '5.4' into 6.0

* 5.4:
  [Validator] Multi decimal to alpha for CssColor validator
  [Console] Fix null handling in formatAndWrap()
  MailerInterface: failed exception contract when enabling messenger
  add nonces to profiler

Author: nicolas-grekas

Mailer.php

@@ -13,8 +13,10 @@
 
 use Psr\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\Mailer\Event\MessageEvent;
+use Symfony\Component\Mailer\Exception\TransportExceptionInterface;
 use Symfony\Component\Mailer\Messenger\SendEmailMessage;
 use Symfony\Component\Mailer\Transport\TransportInterface;
+use Symfony\Component\Messenger\Exception\HandlerFailedException;
 use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Mime\RawMessage;
 
@@ -49,6 +51,15 @@ public function send(RawMessage $message, Envelope $envelope = null): void
             $this->dispatcher->dispatch($event);
         }
 
-        $this->bus->dispatch(new SendEmailMessage($message, $envelope));
+        try {
+            $this->bus->dispatch(new SendEmailMessage($message, $envelope));
+        } catch (HandlerFailedException $e) {
+            foreach ($e->getNestedExceptions() as $nested) {
+                if ($nested instanceof TransportExceptionInterface) {
+                    throw $nested;
+                }
+            }
+            throw $e;
+        }
     }
 }