Bump djangorestframework from 3.16.0 to 3.16.1 in /backend (#1973)

Bumps [djangorestframework](https://github.com/encode/django-rest-framework) from 3.16.0 to 3.16.1.
- [Release notes](https://github.com/encode/django-rest-framework/releases)
- [Commits](encode/django-rest-framework@3.16.0...3.16.1)

---
updated-dependencies:
- dependency-name: djangorestframework
  dependency-version: 3.16.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]