Bump grpcio from 1.45.0 to 1.53.0 in /integration_tests

Bumps [grpcio](https://github.com/grpc/grpc) from 1.45.0 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@v1.45.0...v1.53.0)

---
updated-dependencies:
- dependency-name: grpcio
  dependency-type: direct:production
...

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