Add ftau to the CDI dumps
This block probably needs to get at the ftau fraction too: https://gitlab.cern.ch/atlas-flavor-tagging-tools/algorithms/ftag-docs/-/blob/master/cdi_dumper/python/createCDIOverview.py?ref_type=heads#L23-37
we only give fc here: https://ftag.docs.cern.ch/recommendations/calib/cdi_overview/