chore(deps-dev): bump supertest in /backend in the testing group (#138)

Bumps the testing group in /backend with 1 update: [supertest](https://github.com/ladjs/supertest).


Updates `supertest` from 7.1.4 to 7.2.2
- [Release notes](https://github.com/ladjs/supertest/releases)
- [Commits](forwardemail/supertest@v7.1.4...v7.2.2)

---
updated-dependencies:
- dependency-name: supertest
  dependency-version: 7.2.2
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: testing
...

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