build(deps): update pytest requirement in /backend

Updates the requirements on [pytest](https://github.com/pytest-dev/pytest) to permit the latest version.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/pytest-dev/pytest/compare/8.3.2...8.3.5)

---
updated-dependencies:
- dependency-name: pytest
  dependency-version: 8.3.5
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

backend/requirements.txt

@@ -107,7 +107,7 @@ google-auth-oauthlib
 
 ## Tests
 docker~=7.1.0
-pytest~=8.3.2
+pytest~=8.3.5
 pytest-docker~=3.1.1
 
 googleapis-common-protos==1.63.2