fix: multiple gateway kick user each other.

Signed-off-by: Gordon <46924906+FGadvancer@users.noreply.github.com>

internal/msggateway/hub_server.go

@@ -214,5 +214,5 @@ func (s *Server) MultiTerminalLoginCheck(
 		}
 		s.LongConnServer.SetKickHandlerInfo(i)
 	}
-	return nil, nil
+	return &msggateway.MultiTerminalLoginCheckResp{}, nil
 }