RC action switch threshold defaults

[baumanta]

There are a couple of action switches which trigger a behavior if mapped. The behavior is only triggered if the switch is flipped all the way down. So for 3-position switches (1-2-3) only at position 1.

The action switches behaved differently on manual_control_setpoint due to different thresholds. Example:

RTL switch:
switch up: manual_control_setpoint.return_switch=1 (on)
switch middle: manual_control_setpoint.return_switch=3 (off)
switch down: manual_control_setpoint.return_switch=3 (off)

kill switch:
switch up: manual_control_setpoint.return_switch=1 (on)
switch middle: manual_control_setpoint.return_switch=1 (on) -> not correct
switch down: manual_control_setpoint.return_switch=3 (off)

This PR changes the thresholds to be consistent and correct.

[MaEtUgR]

Thanks for fixing this. I don't see how different default thresholds for the exact same purpose make any sense. And 0.75 is a reasonable default for a two-state input since you can also map it to a three-way switch and get consistent results.