Add current feedback check for brakes

[adeguet1]

It's not trivial to add a safety check on current feedback for motors since the feedback (measured) is not defined solely by the requested (servo). For all back drivable motors, a fair amount of current can be induced by hand motions. For all brakes (ECM, SUJ and PSM-S), we should be able to add a simple check to make sure that the measured current is close to the requested one.