longhorn: list Argo CD's pre-delete finalizers

Argo CD 3.x adds pre-delete-finalizer.argocd.argoproj.io and its /cleanup variant to Applications with PreDelete hooks, which the Longhorn chart has. With only resources-finalizer in git, the apps app-of-apps stayed OutOfSync on helm-longhorn.

apps/templates/longhorn-helm.yaml

@@ -5,6 +5,10 @@ metadata:
   namespace: argocd
   finalizers:
   - resources-finalizer.argocd.argoproj.io
+  # Argo CD 3.x adds these for apps with PreDelete hooks (the Longhorn
+  # chart has one). Listed here so the parent app doesn't see a diff.
+  - pre-delete-finalizer.argocd.argoproj.io
+  - pre-delete-finalizer.argocd.argoproj.io/cleanup
 spec:
   syncPolicy:
     syncOptions: