torque controller: fix non-linear friction #35780
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See example of oscillation due to torque controller/friction: commaai/opendbc#2506
LatControlTorque was made to error-correct in torque space long ago (#27696) when introducing the Bolt ff model, as an error of x lateral accel near wheel center wasn't the same as if we were near torque saturation due to the Bolt's non-linearity. It seems more than appropriate to do the same for friction compensation. A delta of x lateral accel near 0 behaves differently than when near saturation all the same.
This doesn't fully fix the case here commaai/opendbc#2506 due to the insane error, but drastically improves smoothness while still maintaining the friction. We may want to lower it anyway.
This is that route replayed with this PR: