build(deps): bump googleapis-common-protos in /backend

Bumps [googleapis-common-protos](https://github.com/googleapis/google-cloud-python) from 1.63.2 to 1.70.0.
- [Release notes](https://github.com/googleapis/google-cloud-python/releases)
- [Changelog](https://github.com/googleapis/google-cloud-python/blob/main/packages/google-cloud-documentai/CHANGELOG.md)
- [Commits](https://github.com/googleapis/google-cloud-python/commits/googleapis-common-protos-v1.70.0)

---
updated-dependencies:
- dependency-name: googleapis-common-protos
  dependency-version: 1.70.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

backend/requirements.txt

@@ -118,7 +118,7 @@ docker~=7.1.0
 pytest~=8.4.1
 pytest-docker~=3.1.1
 
-googleapis-common-protos==1.63.2
+googleapis-common-protos==1.70.0
 google-cloud-storage==2.19.0
 
 azure-identity==1.23.0