Bump pytest from 9.1.0 to 9.1.1 in /backend

Bumps [pytest](https://github.com/pytest-dev/pytest) from 9.1.0 to 9.1.1.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@9.1.0...9.1.1)

---
updated-dependencies:
- dependency-name: pytest
  dependency-version: 9.1.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

backend/src/requirements_docker.txt

@@ -7,7 +7,7 @@ httpx==0.28.1
 isort==8.0.1
 psycopg2-binary==2.9.12
 pydantic==2.13.4
-pytest==9.1.0
+pytest==9.1.1
 pytest-asyncio==1.4.0
 pytest-cov==7.1.0
 pytest-mock==3.15.1