deps(python): bump google-auth from 2.45.0 to 2.47.0 in /backend

Bumps [google-auth](https://github.com/googleapis/google-auth-library-python) from 2.45.0 to 2.47.0.
- [Release notes](https://github.com/googleapis/google-auth-library-python/releases)
- [Changelog](https://github.com/googleapis/google-auth-library-python/blob/main/CHANGELOG.md)
- [Commits](googleapis/google-auth-library-python@v2.45.0...v2.47.0)

---
updated-dependencies:
- dependency-name: google-auth
  dependency-version: 2.47.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/pyproject.toml

@@ -36,7 +36,7 @@ dependencies = [
     "fastavro==1.12.1",
     "fonttools==4.61.1",
     "frozenlist==1.7.0",
-    "google-auth==2.45.0",
+    "google-auth==2.47.0",
     "googleapis-common-protos==1.70.0",
     "greenlet==3.3.0",
     "grpcio==1.76.0",