fix(cli): support application in any namespace with argocd app diff (…

…#13978) (#13980) (#14061)

Closes #13978.

Signed-off-by: mugioka <okamugi0722@gmail.com>
Co-authored-by: mugi <62197019+mugioka@users.noreply.github.com>

cmd/argocd/commands/app.go

@@ -1034,7 +1034,7 @@ func findandPrintDiff(ctx context.Context, app *argoappv1.Application, resources
 			unstructureds = append(unstructureds, obj)
 		}
 		groupedObjs := groupObjsByKey(unstructureds, liveObjs, app.Spec.Destination.Namespace)
-		items = groupObjsForDiff(resources, groupedObjs, items, argoSettings, app.Name)
+		items = groupObjsForDiff(resources, groupedObjs, items, argoSettings, app.InstanceName(argoSettings.ControllerNamespace))
 	} else if diffOptions.serversideRes != nil {
 		var unstructureds []*unstructured.Unstructured
 		for _, mfst := range diffOptions.serversideRes.Manifests {
@@ -1043,7 +1043,7 @@ func findandPrintDiff(ctx context.Context, app *argoappv1.Application, resources
 			unstructureds = append(unstructureds, obj)
 		}
 		groupedObjs := groupObjsByKey(unstructureds, liveObjs, app.Spec.Destination.Namespace)
-		items = groupObjsForDiff(resources, groupedObjs, items, argoSettings, app.Name)
+		items = groupObjsForDiff(resources, groupedObjs, items, argoSettings, app.InstanceName(argoSettings.ControllerNamespace))
 	} else {
 		for i := range resources.Items {
 			res := resources.Items[i]