Individual sample colour preferences on Concordia should carry over to combined "Unknowns" plot

[NicoleRayner]

I just noticed that if I change the colours of the ellipses of individual samples, when I return to the combined "unknowns" plot that these preferences don't stick - all ellipses are the same default colour. Obviously the other preferences like 1s vs 2s vs 95% conf can't be a mix/match on a single plot (stick with default 2s), but the colour choices should synch with what was selected for each sample individually.