Bump qs, firebase-admin and express in /functions/testapp/functions

Bumps [qs](https://github.com/ljharb/qs) to 6.14.1 and updates ancestor dependencies [qs](https://github.com/ljharb/qs), [firebase-admin](https://github.com/firebase/firebase-admin-node) and [express](https://github.com/expressjs/express). These dependencies need to be updated together.


Updates `qs` from 6.4.0 to 6.14.1
- [Changelog](https://github.com/ljharb/qs/blob/main/CHANGELOG.md)
- [Commits](ljharb/qs@v6.4.0...v6.14.1)

Updates `firebase-admin` from 5.10.0 to 13.6.0
- [Release notes](https://github.com/firebase/firebase-admin-node/releases)
- [Changelog](https://github.com/firebase/firebase-admin-node/blob/main/CHANGELOG.md)
- [Commits](firebase/firebase-admin-node@v5.10.0...v13.6.0)

Updates `express` from 4.16.3 to 4.22.1
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/v4.22.1/History.md)
- [Commits](expressjs/express@4.16.3...v4.22.1)

---
updated-dependencies:
- dependency-name: qs
  dependency-version: 6.14.1
  dependency-type: indirect
- dependency-name: firebase-admin
  dependency-version: 13.6.0
  dependency-type: direct:production
- dependency-name: express
  dependency-version: 4.22.1
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]