To reproduce the issue please build docker container and run

composer install

/var/www/bin/console app:test

Exception will be thrown:

No transport supports the given Messenger DSN. Run "composer require symfony/amqp-messenger" to install AMQP transport. 

But it should not, because environment is dev, composer require-dev section contains symfony/amqp-messenger dependency

In my opinion exception is occurred because AmqpTransportFactory is not registered by framework-bundle.

Unfortunately I don't have strong symfony knowledge to make fix by myself