fix(group_common_events.py): Ignoring "Could not retrieve CDC streams" error
fix(group_common_events.py): Ignoring "Could not retrieve CDC streams" error

* https://github.com/scylladb/scylla/issues/7817

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