build(deps): bump cryptography from 40.0.2 to 43.0.1 in /backend

Bumps [cryptography](https://github.com/pyca/cryptography) from 40.0.2 to 43.0.1.
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](pyca/cryptography@40.0.2...43.0.1)

---
updated-dependencies:
- dependency-name: cryptography
  dependency-type: direct:production
...

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