Add MessageStreamId to Postmark Transport again (#38748)

Author: Jubeki

src/Illuminate/Mail/MailManager.php

@@ -288,10 +288,17 @@ protected function createPostmarkTransport(array $config)
     {
         $factory = new PostmarkTransportFactory();
 
+        $options = isset($config['message_stream_id'])
+                    ? ['message_stream' => $config['message_stream_id']]
+                    : [];
+
         return $factory->create(new Dsn(
             'postmark+api',
             'default',
-            $config['token'] ?? $this->app['config']->get('services.postmark.token')
+            $config['token'] ?? $this->app['config']->get('services.postmark.token'),
+            null,
+            null,
+            $options
         ));
     }