fix(editor): Fix dialogVisibleChanged hooks event when meta.value is undefined (no-changelog) (#7986)

## Summary
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changes. Photos and videos are recommended.

In specific scenarios `meta.value` can come as `undefined`, causing the
hook to fail.

#### How to test the change:
1. Close Expression editor modal dialog with empty value


## Issues fixed
Include links to Github issue or Community forum post or **Linear
ticket**:
> Important in order to close automatically and provide context to
reviewers


https://linear.app/n8n/issue/N8N-7084/typeerror-evalueslice-is-not-a-function-in-evalueslice1-evalueslice-is
https://n8nio.sentry.io/issues/4715787194/


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- [ ] [Docs updated](https://github.com/n8n-io/n8n-docs) or follow-up
ticket created.
- [ ] Tests included.
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packages/editor-ui/src/hooks/cloud.ts

@@ -268,7 +268,7 @@ export const n8nCloudHooks: PartialDeep<ExternalHooks> = {
 		dialogVisibleChanged: [
 			(_, meta) => {
 				const segmentStore = useSegment();
-				const currentValue = meta.value.slice(1);
+				const currentValue = meta.value?.slice(1) ?? '';
 				let isValueDefault = false;
 
 				switch (typeof meta.parameter.default) {