Handle empty mutation cohorts without failing#7

FerriolCalvet with Copilot wants to merge 2 commits into

dev/mutabilitiesbbglab/oncodriveclustl:dev/mutabilitiesfrom

copilot/fix-error-on-no-genesbbglab/oncodriveclustl:copilot/fix-error-on-no-genesCopy head branch name to clipboard