Avoid division by 0 when computing partition

[acogoluegnes]

rabbitmq-stream-java-client/src/main/java/com/rabbitmq/stream/impl/HashRoutingStrategy.java

Line 40 in 317b40c

partitions.get(Integer.remainderUnsigned(hashValue, partitions.size())));

The routing strategy should return the empty list if there is no partition.

The creation of the super stream producer could also fail if there's no partition at that time.