chore(deps): bump fastapi from 0.115.4 to 0.115.8 in /backend

Bumps [fastapi](https://github.com/fastapi/fastapi) from 0.115.4 to 0.115.8.
- [Release notes](https://github.com/fastapi/fastapi/releases)
- [Commits](fastapi/fastapi@0.115.4...0.115.8)

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

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

backend/requirements.txt

@@ -1,7 +1,7 @@
 # Requirements
 beautifulsoup4==4.12.3
 black==24.10.0
-fastapi==0.115.4
+fastapi==0.115.8
 gunicorn==23.0.0 
 httpx==0.27.2
 pip==24.3.1