Bump uvicorn from 0.49.0 to 0.50.2 in /backend

Bumps [uvicorn](https://github.com/Kludex/uvicorn) from 0.49.0 to 0.50.2.
- [Release notes](https://github.com/Kludex/uvicorn/releases)
- [Changelog](https://github.com/Kludex/uvicorn/blob/main/docs/release-notes.md)
- [Commits](Kludex/uvicorn@0.49.0...0.50.2)

---
updated-dependencies:
- dependency-name: uvicorn
  dependency-version: 0.50.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/requirements-docker.txt

@@ -5,4 +5,4 @@ httpx==0.28.1
 pydantic==2.13.4
 python-multipart==0.0.32
 python-jose==3.5.0
-uvicorn==0.49.0
+uvicorn==0.50.2

backend/src/requirements_docker.txt

@@ -14,4 +14,4 @@ pytest-mock==3.15.1
 python-jose==3.5.0
 python-multipart==0.0.32
 SQLAlchemy==2.0.51
-uvicorn==0.49.0
+uvicorn==0.50.2