Bump @grpc/grpc-js and firebase-admin in /functions/functions

Bumps [@grpc/grpc-js](https://github.com/grpc/grpc-node) to 1.10.9 and updates ancestor dependency [firebase-admin](https://github.com/firebase/firebase-admin-node). These dependencies need to be updated together.


Updates `@grpc/grpc-js` from 1.1.8 to 1.10.9
- [Release notes](https://github.com/grpc/grpc-node/releases)
- [Commits](https://github.com/grpc/grpc-node/commits/@grpc/[email protected])

Updates `firebase-admin` from 9.1.1 to 12.1.1
- [Release notes](https://github.com/firebase/firebase-admin-node/releases)
- [Commits](firebase/firebase-admin-node@v9.1.1...v12.1.1)

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

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