fix: Ensure proper shutdown of the cluster in CassandraOnlineStore

sdk/python/feast/infra/online_stores/contrib/cassandra_online_store/cassandra_online_store.py

@@ -395,6 +395,7 @@ def online_write_batch(
                 print(f"Error writing a batch: {exc}")
                 raise Exception("Error writing a batch") from exc
         session.shutdown()
+        self._cluster.shutdown()
         # correction for the last missing call to `progress`:
         if progress:
             progress(1)