[FEATURE] introduce dedicated healthy metrics for every local disk

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

### Search before asking

- [X] I have searched in the [issues](https://github.com/apache/incubator-uniffle/issues?q=is%3Aissue) and found no similar issues.

### Describe the feature

introduce dedicated healthy metrics for every local disk

### Motivation

_No response_

### Describe the solution

_No response_

### Additional context

_No response_

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

The issue names no files, tests, or entry points. Start by locating how local disks are currently monitored and where their metrics are defined; confirm the expected per-disk health signals with maintainers, then add coverage showing that every local disk receives a dedicated healthy metric.

Written by the indexing model from the issue text.