Can't connect to Inav-Configurator on Linux after connection with HIL

[sevrugin]

Steps to reproduce: 1 run XPlane and connect to flight-controller (from plugin menu) 2 disconnect plugin (from plugin menu) 3 try to connect with inav-confaigurator - failed

But! If after the step 2 we will connect to the port by terminal: screen /dev/ttyACM0 115200 and then killall screen we will be able to connect by inav-configurator

In my mind, after we closed the serial port in plugin we still have some unflashed data Also, it would be great to add if (isConnected()) to each methods