Bump pydantic-settings from 2.7.0 to 2.7.1 in /backend

Bumps [pydantic-settings](https://github.com/pydantic/pydantic-settings) from 2.7.0 to 2.7.1.
- [Release notes](https://github.com/pydantic/pydantic-settings/releases)
- [Commits](pydantic/pydantic-settings@v2.7.0...v2.7.1)

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

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

backend/pyproject.toml

@@ -23,7 +23,7 @@ dependencies = [
     "orjson==3.10.13",
     "pwdlib[argon2]==0.2.1",
     "pydantic[email]==2.10.4",
-    "pydantic-settings==2.7.0",
+    "pydantic-settings==2.7.1",
     "pyjwt==2.10.1",
     "python-multipart==0.0.20",
     "uvicorn==0.34.0",