Client repeat registration when unload a bundle

**Describe the bug**
One client has about 500 producers or consumers which belongs to different bundles. When unloading a bundle, some producers or consumers which do not belong to the bundle will register again such as:
2021-09-18 16:28:37,000 [ForkJoinPool.commonPool-worker-12] INFO org.apache.pulsar.broker.service.ServerCnx - [/xx.xx.xx.aa:51064] Created new producer: Producer{topic=PersistentTopic{topic=persistent://public/default/iot-pulsar-press-abcdefghijklABCDEFGHIJKLM-227091}, client=/xx.xx.xx.aa:51064, producerName=pulsar-cluster-iot-1-24844, producerId=1091}

The client log is as follows:
2021-09-18 16:28:33,036 [ ERROR ] ClientCnx - [id: 0x08ccf95e, L:/xx.xx.xx.aa:38706 - R:pulsar-broker-test.docker.ys/xx.xx.xx.bb:6650] Close connection because received internal-server error java.lang.IllegalStateException: Namespace bundle public/default/0x1c000000_0x20000000 is being unloaded
2021-09-18 16:28:33,490 [ INFO ] ClientCnx - [id: 0x08ccf95e, L:/xx.xx.xx.aa:38706 ! R:pulsar-broker-test.docker.ys/xx.xx.xx.bb:6650] Disconnected
2021-09-18 16:28:34,351 [ INFO ] ConnectionHandler - [persistent://public/default/iot-pulsar-press-abcdefghijklABCDEFGHIJKLM-227091] [pulsar-cluster-iot-1-24844] Closed connection [id: 0x08ccf95e, L:/xx.xx.xx.aa:38706 ! R:pulsar-broker-test.docker.ys/xx.xx.xx.bb:6650] -- Will try again in 0.1 s
2021-09-18 16:28:34,651 [ INFO ] ConnectionHandler - [persistent://public/default/iot-pulsar-press-abcdefghijklABCDEFGHIJKLM-227091] [pulsar-cluster-iot-1-24844] Reconnecting after timeout
2021-09-18 16:28:36,987 [ INFO ] ProducerImpl - [persistent://public/default/iot-pulsar-press-abcdefghijklABCDEFGHIJKLM-227091] [pulsar-cluster-iot-1-24844] Creating producer on cnx [id: 0xb51e7cd6, L:/xx.xx.xx.aa:51064 - R:pulsar-broker-test.docker.ys/xx.xx.xx.bb:6650]
2021-09-18 16:28:37,896 [ INFO ] ProducerImpl - [persistent://public/default/iot-pulsar-press-abcdefghijklABCDEFGHIJKLM-227091] [pulsar-cluster-iot-1-24844] Created producer on cnx [id: 0xb51e7cd6, L:/xx.xx.xx.aa:51064 - R:pulsar-broker-test.docker.ys/xx.xx.xx.bb:6650]

The reason is that the client closes the connection when lookup failed in org.apache.pulsar.client.impl.ClientCnx#checkServerError.

```
if (ServerError.ServiceNotReady.equals(error)) {
log.error("{} Close connection because received internal-server error {}", ctx.channel(), errMsg);
ctx.close();
}
```

It will trigger the channel inactive.

```
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
super.channelInactive(ctx);
log.info("{} Disconnected", ctx.channel());
if (!connectionFuture.isDone()) {
connectionFuture.completeExceptionally(new PulsarClientException("Connection already closed"));
}

ConnectException e = new ConnectException(
"Disconnected from server at " + ctx.channel().remoteAddress());

// Fail out all the pending ops
pendingRequests.forEach((key, future) -> future.completeExceptionally(e));
waitingLookupRequests.forEach(pair -> pair.getRight().getRight().completeExceptionally(e));

// Notify all attached producers/consumers so they have a chance to reconnect
producers.forEach((id, producer) -> producer.connectionClosed(this));
consumers.forEach((id, consumer) -> consumer.connectionClosed(this));
transactionMetaStoreHandlers.forEach((id, handler) -> handler.connectionClosed(this));

pendingRequests.clear();
waitingLookupRequests.clear();

producers.clear();
consumers.clear();

timeoutTask.cancel(true);
}
```

In org.apache.pulsar.client.impl.ClientCnx#channelInactive, all the producer or consumer which use the connection will run the function connectionClosed. Then it will reconnect and register again. And some message may be sent failed when failing out all the pending request.

In checkServerError, ServiceNotReady includes some internal-server error, such as IllegalStateException, lookupResult null and some exception. I think the connection is well as it can recieve the reponse from the server. And it will change another connection when reconnectiong (org.apache.pulsar.client.impl.PulsarServiceNameResolver#resolveHost will change another server). Is it necessary to close the connection?

Solution in my opinion:
1.Do not close the connection. But in checkServerError, only ServiceNotReady and TooManyRequests is processed. Is there some issue lead to close the connection?
2.Add another error code. As ServiceNotReady is used in many other places, it may lead other problems.

Which one is better? Or other solution?

Thanks.