Representation for datasets/atlases that don't have human samples

[anngvu]

We have datasets/atlases that don't have human samples from mechanistic/functional assays (e.g. protein-interaction assays). These are still relevant to BRCA mechanisms of action and should be represented in the portal.

• Test what happens when these atlases/datasets are exported without any linked cases or biospecimens
• Maybe add some label for these atlases/datasets to make it clear that they are non-clinical so it's not weird that counts for biospecimens or cases = 0?