argocd: sync Argo CD itself with server-side apply

Required from 3.3, whose ApplicationSet CRD no longer fits the last-applied annotation of client-side apply. Turned on while still on 3.2 so the managed-field migration happens before the CRD grows.

apps/templates/argocd-folder.yaml

@@ -14,5 +14,8 @@ spec:
   syncPolicy:
     syncOptions:
     - CreateNamespace=true
+    # From Argo CD 3.3 the ApplicationSet CRD is too big for client-side
+    # apply's last-applied annotation.
+    - ServerSideApply=true
     automated:
       selfHeal: true