fix: remove serviceName from StatefulSets (not needed)

Removed serviceName field from both StatefulSets since stable pod DNS
is not required for single-replica IRC applications. StatefulSets only
need serviceName when using headless Services for stable network identities.

Also removed statefulset-has-servicename ignore since it's now properly fixed.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

znc/statefulset.yaml

@@ -13,7 +13,6 @@ spec:
     matchLabels:
       app.kubernetes.io/name: znc
       app.kubernetes.io/instance: znc
-  serviceName: "znc"
   replicas: 1
   template:
     metadata: