MySQL JDBC catalog does not recover from a dropped connection

### Apache Iceberg version

1.11.0 (latest release)

### Query engine

Other

### Please describe the bug 🐞

When a MySQL-backed `JdbcCatalog` connection is dropped by the server (for example an idle connection closed at `wait_timeout`), the pool does not recover it:

```
UncheckedSQLException: Failed to execute exists query: SELECT ... FROM iceberg_tables ...
Caused by: com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
Caused by: java.net.SocketException: Broken pipe
```

The failure does not clear on the next call. `ClientPoolImpl.release` returns the client with `addFirst`, so the dead connection goes back to the head of the pool and is handed to the next caller.

`JdbcClientPool` already reconnects on connection failures, but only for `SQLTransientException` and the SQLSTATEs in `COMMON_RETRYABLE_CONNECTION_SQL_STATES`. MySQL's `CommunicationsException` extends `SQLRecoverableException` — a sibling of `SQLTransientException`, not a subtype — and reports SQLSTATE `08S01`, which is not in that set. Neither check matches, so no reconnect is attempted.

Same symptom as #14317.

Proposed fix: treat `SQLRecoverableException` as retryable. The JDBC contract for that type is that recovery requires closing the connection and obtaining a new one, which is what `JdbcClientPool.reconnect` does. Adding `08S01` to the default SQLSTATEs would fix MySQL only.

On existing releases, `retryable_status_codes=08S01` works as a workaround.

PR: #17828

Start with JdbcClientPool's retry checks and reconnect method, then inspect ClientPoolImpl.release to understand how failed clients return to the pool. Review PR #17828 and existing pool tests; done means a dropped MySQL connection is replaced and the next catalog call succeeds without the CommunicationsException recurring.

Written by the indexing model from the issue text.