[INAV 8.0] Have to click flash firmware twice on MacOS

[mmosca]

In MacOS, ports seem to update in two steps (fc com port goes away, DFU port comes up) and sometimes there is a confirmation by the OS if the new connected device (DFU) can be trusted.

The code currently appears to wait for 1 update, and imediatelly fails once the DFU port does not come up at the same time the COM port goes away.