[Task] Ensure XenaBrowser config correctness

[andrewscouten]

They were generated with a script. So far, only BRCA is manually verified.

[andrewscouten]

Where they are located here: https://github.com/collaborativebioinformatics/OncoLearn/tree/main/data/xenabrowser/configs
And you can find GDC TCGA datasets on XenaBrowser here: https://xenabrowser.net/datapages/