Prevent high throttle auto cancelling OSD stats screen on disarm

[breadoven]

If auto landing disarm occurs with the throttle in the high position the stats screen doesn't display because it's immediately auto cancelled by the high throttle stick position. PR prevents this by requiring the throttle stick to be reduced below high before it can be used to cancel the stats screen.

An alternative to avoid this problem is to only allow the stats screen to be cancelled by the pitch stick, a much simpler solution.