Use cleaner test data in csm_camera_plot example notebook

[bpurinton]

Originally on #50:

It would be good to swap in some "clean" test datasets, as the one in the notebook has outliers and is not necessarily representative - this is a minor issue, as I know it is just for testing and development, but these sample figures will inevitably end up used elsewhere, so we should use something that looks good and makes sense, easy to explain, etc.

Perhaps there should be cleaner examples in all the notebooks. Or at least multiple examples.