cubicweb-brainomics #3924898 Fix the files box [validation pending]

It is based on deprecated schema relations

prioritynormal
typebug
done in0.10.0
load0.200
load left0.000
closed by#34f416d7a382 [views] Fix files box, closes #3924898
patch[views] Fix files box, closes #3924898 [applied]