feat: enable Cilium's hubble relay mTLS (#1086)

**What problem does this PR solve?**:
Enables mTLS. The hubble relay server was already always enabled, this
PR also enables its mTLS configuration.

**Which issue(s) this PR fixes**:
Fixes #

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Author: dkoshkin

charts/cluster-api-runtime-extensions-nutanix/addons/cni/cilium/values-template.yaml

@@ -11,6 +11,10 @@ hubble:
       schedule: "0 0 1 * *"       # schedule on the 1st day regeneration of each month
   relay:
     enabled: true
+    tls:
+      server:
+        enabled: true
+        mtls: true
     image:
       useDigest: false
     priorityClassName: system-cluster-critical