RPC now works for 2FA

InABox.Client.RPC/RPCClient.cs

@@ -115,7 +115,7 @@ namespace InABox.Rpc
             var parameters = new RpcCheck2FAParameters()
             {
                 Code = code,
-                SessionId = session ?? Guid.Empty,
+                SessionId = session ?? ClientFactory.SessionID,
             };
             var result = _transport.Send<RpcCheck2FACommand, RpcCheck2FAParameters, RpcCheck2FAResult>(parameters);
             return result.Valid;