Fix: Serial port configuration not applied

[sadounlilya]

When using the Serial connection with the app, the port configuration was never actually updated meaning all received bytes were corrupted.

It is because the config setter is never triggered and sp_set_config() from the libserialport is never called.

This fix creates a new SerialPortConfig object and assigns it via the setter which will call the sp_set_config() to actually update it.