Cherry-picked Feature Request 1267242 from ab98ae54bb. Prevent sharp or ordinary navigation turn desires from being issued unless the corresponding turn signal is active, and add regression coverage for missing and opposite signals.
Co-Authored-By: Prabhaav Pillai <prabhaav@msu.edu>
Blinker turn desire fed the model a turnLeft/turnRight input below lane-change
speed, inflating model_length so the car rolled past stop lines. Gate it in
desire_helper on prior-frame starpilotPlan.redLight/forcingStop/stopSignConfirmed
until standstill, then release so the model still turns through. "Stop first,
then turn."
firestar5683