message: [dbus] close unsecure port when timeout is zero
  This is the behavior of the current client code. Update implementation
  to be compatible.
diff: @@ -382,18 +382,26 @@ otError ThreadHelper::PermitUnsecureJoin(uint16_t aPort, uint32_t aSeconds)
  mNcp->PostTimerTask(triggerTime, [this, aPort]() {
  auto now = std::chrono::steady_clock::now();
  - otExtAddress steeringClearData;
  + otExtAddress noneAddress;
  // 0 to clean steering data
  - memset(&steeringClearData.m8, 0, sizeof(steeringClearData.m8));
  + memset(&noneAddress.m8, 0, sizeof(noneAddress.m8));
  if (now >= mUnsecurePortCloseTime[aPort])
  {
  otIp6RemoveUnsecurePort(mInstance, aPort);
  - otThreadSetSteeringData(mInstance, &steeringClearData);
  + otThreadSetSteeringData(mInstance, &noneAddress);
  mUnsecurePortCloseTime.erase(aPort);
  }
  });
  }
  + else
  + {
  + otExtAddress noneAddress;
  +
  + memset(&noneAddress.m8, 0, sizeof(noneAddress.m8));
  + otIp6RemoveUnsecurePort(mInstance, aPort);
  + otThreadSetSteeringData(mInstance, &noneAddress);
  + }
  exit:
  return error;
  