Disabling an adc counts it as always on, instead of disabled

[Waity5]

Refloat version

1.3.0-beta1

Problem description

Previously, disabling an adc by setting it to 0v would cause the other adc to have complete control over the overal state of the foot sensor. So if that adc is on, the sensor is reported as BOTH, and if it's off, it's reported as NONE

But with refactoring done when adding the adc swapping, that's not the case. Now disabled adc always reports that side as on, so the sensor will either report as BOTH or LEFT/RIGHT. never NONE