RST_STREAM error from grpc via Bidi in Firestore Client Library

[crwilcox]

Implementing a watch/listen in Firestore, waiting a while (some reports of 30, 60, and 120 minutes) results in an unhandled RST_STREAM error. We should investigate if this can be handled.

Related to firebase/firebase-admin-python#282

google-api-core==1.14.3
google-auth==1.7.1
google-cloud-core==1.0.3
google-cloud-firestore==1.6.0
googleapis-common-protos==1.6.0
grpcio==1.25.0

Output and repro code at: https://gist.github.com/crwilcox/0ed944c7afa70a6a78dd8e8e76ebf1fd

[crwilcox]

In Go we retry on far more error codes,
https://github.com/googleapis/google-cloud-go/blob/be07a624a2e4501df135ab7f731b7cfb408d9df2/firestore/watch.go#L507

codes.Unknown, codes.DeadlineExceeded, codes.ResourceExhausted, codes.Internal, codes.Unavailable, codes.Unauthenticated