Removed clientID from NATS-Streaming Config (#6391)

clientID must be a unique `UUID` for each connections. Now, the
server generates it, rather considering the config.

Removing it as it is non-beneficial right now.

Fixes #6364

pkg/madmin/examples/set-config.go

@@ -75,7 +75,6 @@ var configJSON = []byte(`{
 				"streaming": {
 					"enable": false,
 					"clusterID": "",
-					"clientID": "",
 					"async": false,
 					"maxPubAcksInflight": 0
 				}