chore(docs): Fix broken link to Hubble metrics (#1211)

# Description

Fix broken link to Hubble metrics page

## Related Issue

If this pull request is related to any issue, please mention it here.
Additionally, make sure that the issue is assigned to you before
submitting this pull request.

## Checklist

- [x] I have read the [contributing
documentation](https://retina.sh/docs/contributing).
- [x] I signed and signed-off the commits (`git commit -S -s ...`). See
[this
documentation](https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification)
on signing commits.
- [x] I have correctly attributed the author(s) of the code.
- [x] I have tested the changes locally.
- [x] I have followed the project's style guidelines.
- [x] I have updated the documentation, if necessary.
- [x] I have added tests, if applicable.

## Screenshots (if applicable) or Testing Completed


![image](https://github.com/user-attachments/assets/0381fa62-7cd9-40ea-8f6c-6e3f24771801)

## Additional Notes

Add any additional notes or context about the pull request here.

---

Please refer to the [CONTRIBUTING.md](../CONTRIBUTING.md) file for more
information on how to contribute to this project.

docs/03-Metrics/01-metrics-intro.md

@@ -6,7 +6,7 @@ Prometheus metrics available depend on the Retina control plane deployed.
 
 There are two control planes used in the Retina project: Hubble and the legacy control plane. Both control planes create metrics and traces which are generated by the eBPF data plane, which has a single implementation. Only one control plane should be deployed at a given time. Helm charts for the deployment are found under `deploy/hubble/manifests/controller/helm/retina` and `deploy/legacy/manifests/controller/helm/retina`.
 
-1. [Hubble metrics](./hubble_metrics.md)
+1. [Hubble metrics](./02-hubble_metrics.md)
 2. [Legacy metrics](./modes/modes.md)
 
 > Note: Hubble offers additional features and metrics that the legacy control plane does not support. The plan is to deprecate the legacy control plane in favor of Hubble. For further documentation on Hubble, check [Cilium/Hubble repository](https://github.com/cilium/hubble/?tab=readme-ov-file#features) and official [Hubble metrics documentation](https://docs.cilium.io/en/stable/observability/metrics/#hubble-metrics)