chore(deps): bump grpcio from 1.81.0 to 1.81.1 in /backend/python/vllm (#10347)

Bumps [grpcio](https://github.com/grpc/grpc) from 1.81.0 to 1.81.1.
- [Release notes](https://github.com/grpc/grpc/releases)
- [Commits](grpc/grpc@v1.81.0...v1.81.1)

---
updated-dependencies:
- dependency-name: grpcio
  dependency-version: 1.81.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

backend/python/vllm/requirements.txt

@@ -1,4 +1,4 @@
-grpcio==1.81.0
+grpcio==1.81.1
 protobuf
 certifi
 setuptools