Flight Modes setup should not report incomplete when using Joystick

[DonLakeFlyer]

If you are using a Joystick then you don't set up flight modes on an RC channel. It's super annoying when it keeps telling you flight modes aren't set up. This is actually a Herelink problem in that it supports a joystick, but the joystick sends RC signals.

[DonLakeFlyer]

@rjehangir, @patrickelectric Hey ArduSub guys.

I'm trying to figure out the usage of supportsRadio which was added ages ago. You can see it here: https://github.com/mavlink/qgroundcontrol/blob/master/src/AutoPilotPlugins/APM/APMAutoPilotPlugin.cc#L77. It's a bit odd in that it gets rid of radio cal and leaves in flight mode setup. Does ArduSub just have a radio which supports channels and so forth but doesn't need calibration?

I also don't understand why it is used here: https://github.com/mavlink/qgroundcontrol/blob/master/src/UI/toolbar/RCRSSIIndicator.qml#L30. That would seem to indicate that an ArduSub although it has supportRadio=false still sends an rcRSSI value.