[Improve] Show Invalid Token Error Message

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/pulsar-client-cpp/issues) and found nothing similar.

### Version

2.9.3.11+

### Minimal reproduce step

pass an invalid token and try to create a producer

### What did you expect to see?

User error messages that specify the input token is invalid.

Error Checking/Getting Partition Metadata while creating producer on {topicName} -- InvalidToken

### What did you see instead?

Error Checking/Getting Partition Metadata while creating producer on {topicName} -- ConnectError

### Anything else?

Similar stack-overflow questions:

https://stackoverflow.com/questions/62227305/apache-pulsar-error-checking-getting-partition-metadata-while-subscribing

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

Reproduce the issue by passing an invalid token while creating a producer, then trace the partition-metadata error path in the C++ client. Done means the reported error identifies InvalidToken instead of ConnectError, matching the expected message.

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