[Firestore] What is the recommended way to check for an instance of a Firestore error using this package?

Using `firebase-admin`, what is the recommended way to verify an error is Firestore related? And so that typescript knows that the error instance will have the `code` property, etc?

Ideally, I'd be able to verify the error is an instance of [`FirestoreError`](https://firebase.google.com/docs/reference/node/firebase.firestore.FirestoreError), but the error I'm experiencing now seems to be grpc related, as the `code` property is returning a number corresponding to the errors [here](https://github.com/grpc/grpc/blob/master/doc/statuscodes.md).

There [are](https://github.com/firebase/firebase-admin-node/issues/1666) [several](https://github.com/firebase/firebase-admin-node/issues/1741) [issues](https://github.com/firebase/firebase-admin-node/pull/2151) in this repository around getting access to error classes, with no clear answers.

If I'm missing something, please point me in the right direction.