fix(observability): 🐛 add prune + RespectIgnoreDifferences to o12y syncPolicy

Fix CRD bootstrap deadlock on victoria-metrics-k8s-stack ArgoCD app.
Adds prune: true and RespectIgnoreDifferences=true to prevent sync
failures when CRs are applied before CRDs are established.

otc/dev.t09.de/stacks/observability/victoria-k8s-stack.yaml

@@ -9,10 +9,12 @@ spec:
   project: default
   syncPolicy:
     automated:
+      prune: true
       selfHeal: true
     syncOptions:
       - CreateNamespace=true
       - ServerSideApply=true
+      - RespectIgnoreDifferences=true
   destination:
     name: in-cluster
     namespace: observability