ConnectRequest got NOTREADONLY ReplyHeader

I would expect ConnectRequest has two kinds of response in normal conditions: ConnectResponse and socket close. But if sever was configured with readonlymode.enabled but not localSessionsEnabled, then client could get NOTREADONLY in reply to ConnectRequest. I saw, at least, no handling in java client. And, I encountered this in writing tests for rust client.

It guess it is not by design. And we probably could close the socket in early phase. But also, it could be solved in client sides as sizeof(ConnectResponse) is larger than sizeof(ReplyHeader). Then, we gain ability to carry error for ConnectRequest while ConnectResponse does not.