Bump starlette from 0.46.2 to 0.47.0 in /back-end

Bumps [starlette](https://github.com/encode/starlette) from 0.46.2 to 0.47.0.
- [Release notes](https://github.com/encode/starlette/releases)
- [Changelog](https://github.com/encode/starlette/blob/master/docs/release-notes.md)
- [Commits](Kludex/starlette@0.46.2...0.47.0)

---
updated-dependencies:
- dependency-name: starlette
  dependency-version: 0.47.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

back-end/requirements.txt

@@ -12,7 +12,7 @@ pydantic==2.11.5
 python-multipart==0.0.20
 six==1.17.0
 sniffio==1.3.1
-starlette==0.46.2
+starlette==0.47.0
 typing_extensions==4.13.2
 uvicorn==0.34.2
 pytest==8.3.5