Keep gene set expansions associated across moves
Keep gene set expansions associated across moves

The association of a gene set heatmap track with its expansions should
not change when the heatmap moves to a differently numbered track group.


Former-commit-id: 136f69f85ec44e5c625bedf1222bd9631efb02f4
cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,alisman/cbioportal-frontend,alisman/cbioportal-frontend,alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,cBioPortal/cbioportal-frontend,cBioPortal/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend,cBioPortal/cbioportal-frontend,alisman/cbioportal-frontend