Helpful error message if a collection doesn't exist

[mike-gangl]

Not much guidance from CMR if a collection doesn't exist. We should add a check if 0 files are found to ensure that a collection exists. This could save time for a user using this for a non-PO.DAAC provider

[shiang-luong]

I think this is fixed?

raise ValueError(f'No collections found in CMR for {collection_short_name}/{provider}') ValueError: No collections found in CMR for ddd/POCLOUD