They used it on test mules to create labeled training data for their older monocular depth / Occupancy Network models (which they still use as part of the supervisory policy enforcement and active safety layer, alongside the end-to-end model).

They’ve never had LiDAR in their cars and it would not ever have been practical for them to have done so. Nobody has any mid or long range LiDAR in vehicles as the scale that Tesla sells.