JMX: cluster-connection start() method does not work after stop() method invoked

Invoking the `stop()` operation correctly stops a cluster-connection bridge, e.g.

2021-09-01 11:35:44,005 INFO  [org.apache.activemq.artemis.core.server] AMQ221029: stopped bridge $.artemis.internal.sf.my-cluster.0f3bc809-0b39-11ec-a557-8c1645c4c9f4

If the `start()` operation is invoked, the operation feedback indicates it succeeded but it appears the cluster-connection was not actually restarted – no logs indicate it started and the Nodes attribute is `{}`.