EKF: record yaw alignment event during initialisation to allow heading fusion to start early
EKF: record yaw alignment event during initialisation to allow heading fusion to start early

This ensures bad yaw gyro biases are compensated for early, rather than waiting for the tilt alignment to fully converge before fusing heading.

PX4/ecl,PX4/ecl,PX4/ecl,PX4/ecl,PX4/ecl