Clean up 2d grid plot outputs

src/mace_head_pipeline/plot.py

src/mace_head_pipeline/process.py

src/mace_head_pipeline/sensor/hatpro.json

src/mace_head_pipeline/sensor/hatpro.py

src/mace_head_pipeline/sensor/lidar.json

src/mace_head_pipeline/sensor/lidar.py

src/mace_head_pipeline/units.py

test/test_utils.py