Don't show negative or trivial ghost-generic savings on dashboards
Don't show negative or trivial ghost-generic savings on dashboards

Relates to #1348

annapowellsmith/openpresc,annapowellsmith/openpresc,ebmdatalab/openprescribing,ebmdatalab/openprescribing,annapowellsmith/openpresc,ebmdatalab/openprescribing,ebmdatalab/openprescribing,annapowellsmith/openpresc