Bump qs and express in /polling-app-client

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

Updates `qs` from 6.5.2 to 6.5.3
- [Release notes](https://github.com/ljharb/qs/releases)
- [Changelog](https://github.com/ljharb/qs/blob/main/CHANGELOG.md)
- [Commits](ljharb/qs@v6.5.2...v6.5.3)

Updates `express` from 4.16.3 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@4.16.3...4.18.2)

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

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Author: dependabot[bot]