Merge branch '6.4' into 7.0

* 6.4: (24 commits)
  Fix Twig tests
  [Scheduler] Fix tests
  [TwigBridge] Add FormLayoutTestCase class
  Fix CS
  Allow sending scheduled messages through the slack API
  [TwigBridge] Add `AppVariable::getEnabledLocales()` to retrieve the enabled locales
  [RateLimiter] Add missing dependency
  [RateLimiter] Add SlidingWindowLimiter::reserve()
  [Messenger] Add WrappedExceptionsInterface for nested exceptions
  [Mime] Add `TemplatedEmail::locale()` to set the locale for the email rendering
  Fix CS
  [Messenger][Scheduler] Add AsCronTask & AsPeriodicTask attributes
  [Scheduler] Make debug:scheduler output more useful
  [Notifier] Tweak some phpdocs
  [FrameworkBundle] Change BrowserKitAssertionsTrait::getClient() to be protected
  Fix CS
  [FrameworkBundle] Allow BrowserKit relative URL redirect assert
  [Messenger] RejectRedeliveredMessageException should not be retried
  [Serializer] Make `ProblemNormalizer` give details about Messenger’s `ValidationFailedException`
  [WebProfilerBundle] Support `!` negation operator in url filter
  ...

Author: fabpot

Channel/EmailChannel.php

@@ -46,6 +46,9 @@ public function __construct(TransportInterface $transport = null, MessageBusInte
         $this->envelope = $envelope;
     }
 
+    /**
+     * @param EmailRecipientInterface $recipient
+     */
     public function notify(Notification $notification, RecipientInterface $recipient, string $transportName = null): void
     {
         $message = null;

Channel/SmsChannel.php

@@ -22,6 +22,9 @@
  */
 class SmsChannel extends AbstractChannel
 {
+    /**
+     * @param SmsRecipientInterface $recipient
+     */
     public function notify(Notification $notification, RecipientInterface $recipient, string $transportName = null): void
     {
         $message = null;

EventListener/SendFailedMessageToNotifierListener.php

@@ -39,7 +39,8 @@ public function onMessageFailed(WorkerMessageFailedEvent $event): void
 
         $throwable = $event->getThrowable();
         if ($throwable instanceof HandlerFailedException) {
-            $throwable = $throwable->getNestedExceptions()[0];
+            $exceptions = $throwable->getWrappedExceptions();
+            $throwable = $exceptions[array_key_first($exceptions)];
         }
         $envelope = $event->getEnvelope();
         $notification = Notification::fromThrowable($throwable)->importance(Notification::IMPORTANCE_HIGH);