Bump qs and express in /backend

Bumps [qs](https://github.com/ljharb/qs) to 6.11.0 and updates ancestor dependency [express](https://github.com/expressjs/express). These dependencies need to be updated together.


Updates `qs` from 6.10.1 to 6.11.0
- [Release notes](https://github.com/ljharb/qs/releases)
- [Changelog](https://github.com/ljharb/qs/blob/main/CHANGELOG.md)
- [Commits](ljharb/qs@v6.10.1...v6.11.0)

Updates `express` from 4.16.4 to 4.18.2
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](expressjs/express@4.16.4...4.18.2)

---
updated-dependencies:
- dependency-name: qs
  dependency-type: indirect
- dependency-name: express
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>