build(deps-dev): bump @grpc/proto-loader from 0.6.7 to 0.6.9

Bumps [@grpc/proto-loader](https://github.com/grpc/grpc-node) from 0.6.7 to 0.6.9.
- [Release notes](https://github.com/grpc/grpc-node/releases)
- [Commits](https://github.com/grpc/grpc-node/commits/@grpc/proto-loader@0.6.9)

---
updated-dependencies:
- dependency-name: "@grpc/proto-loader"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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