[BUG] Cluster Does Not Become Reachable

## Bug Description

Cluster registration completes successfully, but the newly registered cluster does not become reachable. The cluster is added to AKS desktop, however connectivity is never established and the cluster cannot be used after registration.

## Steps to Reproduce

1. Open AKS desktop.
2. Navigate to Cluster Registration.
3. Select an AKS Hybrid / Edge (Arc-connected) cluster.
4. Complete the registration workflow.
5. Wait for registration to finish.
6. Observe cluster status after registration.

## Expected Behavior

After successful registration, the cluster should become reachable, be added to the kubeconfig, and be available for management within AKS desktop.

## Actual Behavior

The registration workflow completes, but the cluster remains unreachable. AKS desktop reports that the cluster was added but did not become reachable, preventing users from accessing or managing the cluster.

## Screenshots

## Environment

- **Plugin Version**: [0.9.0]
- **Headlamp Version**: [0.43.0]
- **Kubernetes Version**: [1.34.3]
- **Azure CLI Version**: [na]
- **Browser**: [na]
- **OS**: [e.g. macOS 26.6.1]

## Additional Context

Issue observed while registering an AKS Hybrid / Edge (Arc-connected) cluster. Registration appears to succeed, but connectivity is never established. The cluster remains unavailable for use after the workflow completes.

## Logs

Cluster 'santhosh-aug-bm' was added, but it did not become reachable. The cluster may be stopped or its Azure Arc agents may be offline. Details: The proxy did not add the cluster to kubeconfig in time.

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## Checklist

- [ ] I have searched for existing issues
- [ ] I have provided all necessary information
- [ ] I have tested with the latest version
- [ ] I have included steps to reproduce