Add “Open Hubble UI” button when Cilium is used as the CNI

[rajaSahil]

What would you like to be added? / User Story:

As a user or cluster administrator, I would like to access Hubble UI directly from the KKP dashboard when Cilium is enabled, in order to quickly view network flows, service connectivity, and troubleshoot Cilium-related networking issues.

When a user cluster is running Cilium as the CNI, it would be very helpful to provide a dedicated Open Hubble UI button in the KKP dashboard, similar to the existing Open Dashboard button for the Kubernetes Dashboard.

Expected Behaviour:

• Detect if the cluster uses Cilium as the CNI.
• If yes, show a button (e.g., “Open Hubble UI”).

Internal reference: 8482