Allow resume after `create-dataset`

[hannah-rae]

Currently if you want to refine the selected images or anything else after create-dataset you have to redo the selection progress already made.

If you run select-images after create-dataset (e.g., increasing the cloud cover to select images for skipped chips) it restarts the selections for all chips not just the skipped ones.

However, if you run select-images multiple times, it will skip chips that have already had images selected.