dillon1000/react

[playground] Refactor ConfigEditor to use <Activity> component (#34958)

## Summary

This PR addresses a pending TODO comment left in
https://github.com/facebook/react/pull/34499


https://github.com/facebook/react/blame/eb2f784e752ba690f032db4c3d87daac77a5a2aa/compiler/apps/playground/components/Editor/ConfigEditor.tsx#L37

This change removes the temporary workaround and replaces it with
`<Activity>`, as originally intended.

## How did you test this change?

- Updated the component to use `<Activity>` directly
- Verified the editor renders correctly in both development and
production builds.
- The `<Activity>` UI updates as expected.



https://github.com/user-attachments/assets/ce976123-da59-4579-b063-b308a9167b21