Add tabletServerEpoch to prevent offline tabletServer send requests to coordinator and wrongly handle

### Search before asking

- [x] I searched in the [issues](https://github.com/alibaba/fluss/issues) and found nothing similar.

### Motivation

In #1142. We will introduce a new request of controlled shutdown, which will inform the `coordinatorServer` to migrate the bucket leader on this server through retries before the `tabletServer` goes offline. However, we need a mechanism to ensure that if an offline `tabletServer `sends a controlled shutdown request (abnormal situation), the `coordinatorServer` should ignore this request; otherwise, it would incorrectly take the leader on the new `tabletServer` offline.

### Solution

_No response_

### Anything else?

_No response_

### Willingness to contribute

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

Start by reading the controlled-shutdown work described in #1142 and tracing requests between the tabletServer and coordinatorServer. Determine where server epochs would be carried and checked, then verify that a request from an offline tabletServer is ignored without taking the replacement tabletServer's leader offline.

Written by the indexing model from the issue text.