Bump python from 3.13.2-bookworm to 3.14.0-bookworm in /backend

Bumps python from 3.13.2-bookworm to 3.14.0-bookworm.

---
updated-dependencies:
- dependency-name: python
  dependency-version: 3.14.0-bookworm
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

backend/Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 
-FROM python:3.13.2-bookworm AS sphinx-docs
+FROM python:3.13.8-bookworm AS sphinx-docs
 
 # Prevents Python from writing pyc files, and from buffering stdout and stderr to avoid situations where the application crashes without emitting any logs due to buffering.
 ENV PYTHONDONTWRITEBYTECODE=1 \