Bump @grpc/grpc-js and firebase

Bumps [@grpc/grpc-js](https://github.com/grpc/grpc-node) to 1.9.15 and updates ancestor dependency [firebase](https://github.com/firebase/firebase-js-sdk). These dependencies need to be updated together.


Updates `@grpc/grpc-js` from 1.8.18 to 1.9.15
- [Release notes](https://github.com/grpc/grpc-node/releases)
- [Commits](https://github.com/grpc/grpc-node/compare/@grpc/grpc-js@1.8.18...@grpc/grpc-js@1.9.15)

Updates `firebase` from 10.0.0 to 10.12.2
- [Release notes](https://github.com/firebase/firebase-js-sdk/releases)
- [Changelog](https://github.com/firebase/firebase-js-sdk/blob/master/CHANGELOG.md)
- [Commits](https://github.com/firebase/firebase-js-sdk/compare/firebase@10.0.0...firebase@10.12.2)

---
updated-dependencies:
- dependency-name: "@grpc/grpc-js"
  dependency-type: indirect
- dependency-name: firebase
  dependency-type: direct:development
...

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