Consider more contrasting peer points in the funnel plots

[DCEW]

Internal proxy user interviews revealed some issues with the visibility of points on the funnel plot - shades of grey were not easy enough to distinguish. Could we consider having peers be a different colour perhaps?

[matt-dray]

Currently in the funnel (and box) plot, peers are black circles and the focus is solid red. Could make the peers solid black. The remaining dots in the funnel are all remaining units (i.e. non-peers) that shouldn't draw attention; they're there because they factor into the calculation of the funnel limits.

Regardless, there could be better linking of peers vs not-peers across the trend, funnel and box. For example, the trend only shows peers, but they're light grey, which doesn't match their theming in the funnel (outlined black). The box doesn't show all non-peers, but the plot does use them for calculation, so they should be shown for the same reason we show them in the funnel.

Were the users looking at the most recent version of the app? I know we've altered the chart points/lines a couple of times.