RabbitQueue throws AMQPTimeoutException after timeout with `--exit-after`

[paxuclus]

The job:work command of the Flowpack.JobQueue.Common package supports the parameter --exit-after which allows to set a time limit after which the command exists.

If during that time no message is published to the RabbitMQ queue, an AMQPTimeoutException is thrown, setting the exit code of the job:work process to 1.

Expected behavior:
If no message is found in time, the RabbitQueue should return null as stated in the PHPDoc of the QueueInterface (See here).