[hotfix] Fix namespace for kube-prometheus-stack 7 (!126)

Co-authored-by: denis.patrakeev <denis.patrakeev@avroid.tech>
Reviewed-on: https://git.avroid.tech/K8s/k8s-configs/pulls/126
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

@@ -9,8 +9,8 @@ metadata:
 spec:
   project: kube-prometheus-stack
   destination:
-    - namespace: kube-prometheus-stack
     server: https://kubernetes.default.svc
+    namespace: kube-prometheus-stack
   sources:
     - repoURL: https://git.avroid.tech/K8s/k8s-configs.git
       targetRevision: master