Fix redis-cli CLUSTER SETSLOT race conditions (#10381)

After migrating a slot, send CLUSTER SETSLOT NODE to the destination
node first to make sure the slot isn't left without an owner in case
the destination node crashes before it is set as new owner.

When informing the source node, it can happen that the destination
node has already informed it and if the source node has lost its
last slot, it has already turned itself into a replica. Redis-cli
should ignore this error in this case.