Switch X and Y axes for PPU bubble charts
Switch X and Y axes for PPU bubble charts

Given that presentation names can be long and that there can be
arbitrarily many of them on a given chart, it makes more sense to have
these on the Y axis as we can extend the height of the chart but not its
width.

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