[BUG] ssh monitor with proxyjump, triggering "Too many authentication failures" exception

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Current Behavior

The global singleton sshClient was shared across all connections, causing identity (passwords/keys) to accumulate globally. When with ProxyJump - authentication attempts would mix identities from different sessions, exceeding the server's MaxAuthTries and triggering "Too many authentication failures".

### Expected Behavior

_No response_

### Steps To Reproduce

_No response_

### Environment

```markdown
HertzBeat version(s): 1.7+
```

### Debug logs

_No response_

### Anything else?
#3926
_No response_

Start by locating the SSH monitor connection setup and the global singleton sshClient described in the issue, then trace how ProxyJump sessions collect identities. Reproduce the authentication-failure case if possible; done means separate sessions no longer mix credentials or trigger the server's "Too many authentication failures" error.

Written by the indexing model from the issue text.