No null terminator in Ros1, so don't truncate the string.

Author: LaurieCheers-unity

src/ros_tcp_endpoint/server.py

@@ -113,7 +113,7 @@ def handle_syscommand(self, topic, data):
         if function is None:
             self.send_unity_error("Don't understand SysCommand.'{}'".format(topic))
         else:
-            message_json = data.decode("utf-8")[:-1]
+            message_json = data.decode("utf-8")
             params = json.loads(message_json)
             function(**params)