Bump the production-dependencies group across 1 directory with 2 updates

Bumps the production-dependencies group with 2 updates in the /backend directory: [express](https://github.com/expressjs/express) and [@types/express](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/express).


Updates `express` from 4.21.2 to 5.1.0
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](expressjs/express@4.21.2...v5.1.0)

Updates `@types/express` from 4.17.21 to 5.0.1
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/express)

---
updated-dependencies:
- dependency-name: express
  dependency-version: 5.1.0
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: production-dependencies
- dependency-name: "@types/express"
  dependency-version: 5.0.1
  dependency-type: direct:development
  update-type: version-update:semver-major
  dependency-group: production-dependencies
...

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

Author: dependabot[bot]