StreamAllMessage and Groups create inconsistent results

[nplasterer]

When streaming Groups & StreamAllMessages at the same time sometimes stream all messages receives the welcome message first and writes it to the database. This means when groups receives the stream it think it already exists and doesn't stream the message.

[nplasterer]

From andrew

We could probably just:
Keep a list/keep the last streamed group
if we get the error that welcome id exists, silence the error and stream the group anyway if it's a newer group than the last known streamed group