[hotfix] Fix namespace for kube-prometheus-stack 6 (!125)

Co-authored-by: denis.patrakeev <denis.patrakeev@avroid.tech>
Reviewed-on: https://git.avroid.tech/K8s/k8s-configs/pulls/125
Reviewed-by: Rustam Tagaev <rustam.tagaev@avroid.team>

clusters/k8s-avroid-office.prod.local/namespaces/kube-prometheus-stack/kube-prometheus-stack/argocd-apps-kube-prometheus-stack-app.yaml

@@ -11,8 +11,6 @@ spec:
   destination:
     - namespace: kube-prometheus-stack
       server: https://kubernetes.default.svc
-    - namespace: kube-system
-      server: https://kubernetes.default.svc
   sources:
     - repoURL: https://git.avroid.tech/K8s/k8s-configs.git
       targetRevision: master