Bump grpcio from 1.51.1 to 1.53.0 in /python/backend

Bumps [grpcio](https://github.com/grpc/grpc) from 1.51.1 to 1.53.0.
- [Release notes](https://github.com/grpc/grpc/releases)
- [Changelog](https://github.com/grpc/grpc/blob/master/doc/grpc_release_schedule.md)
- [Commits](grpc/grpc@v1.51.1...v1.53.0)

---
updated-dependencies:
- dependency-name: grpcio
  dependency-type: indirect
...

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