Bump @babel/helpers in /modules/contentbox/themes/default

Bumps [@babel/helpers](https://github.com/babel/babel/tree/HEAD/packages/babel-helpers) from 7.18.2 to 7.26.10.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/main/CHANGELOG.md)
- [Commits](https://github.com/babel/babel/commits/v7.26.10/packages/babel-helpers)

---
updated-dependencies:
- dependency-name: "@babel/helpers"
  dependency-type: indirect
...

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