chore(deps): bump qs and formidable in /sample/15-mvc

Bumps [qs](https://github.com/ljharb/qs) and [formidable](https://github.com/node-formidable/formidable). These dependencies needed to be updated together.

Updates `qs` from 6.9.3 to 6.10.3
- [Release notes](https://github.com/ljharb/qs/releases)
- [Changelog](https://github.com/ljharb/qs/blob/main/CHANGELOG.md)
- [Commits](ljharb/qs@v6.9.3...v6.10.3)

Updates `formidable` from 2.0.1 to 2.1.1
- [Release notes](https://github.com/node-formidable/formidable/releases)
- [Changelog](https://github.com/node-formidable/formidable/blob/master/CHANGELOG.md)
- [Commits](https://github.com/node-formidable/formidable/commits)

---
updated-dependencies:
- dependency-name: qs
  dependency-type: indirect
- dependency-name: formidable
  dependency-type: indirect
...

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