dependency: (deps): bump openai from 1.35.7 to 1.35.9 in /backend (#168)

Bumps [openai](https://github.com/openai/openai-python) from 1.35.7 to 1.35.9.
- [Release notes](https://github.com/openai/openai-python/releases)
- [Changelog](https://github.com/openai/openai-python/blob/main/CHANGELOG.md)
- [Commits](openai/openai-python@v1.35.7...v1.35.9)

---
updated-dependencies:
- dependency-name: openai
  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>

backend/requirements.txt

@@ -29,7 +29,7 @@ inflection==0.5.1
 kiwisolver==1.4.5
 matplotlib==3.9.0
 numpy==1.26.4
-openai==1.35.7
+openai==1.35.9
 opencv-python==4.10.0.84
 packaging==23.2
 pdfminer.six==20231228