fix(nemesis): ignore ycsb `Connection refused` on terminating a node
fix(nemesis): ignore ycsb `Connection refused` on terminating a node

`disrupt_terminate_and_replace_node` was getting `Connection refused`
which is to be excpected since the dynamodb client isn't node aware
and we don't have loadblancers

scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests