Status page: revisit color scheme for the progress bar in the migration details page

_Originally posted by @h-vetinari in https://github.com/conda-forge/conda-forge.github.io/issues/2137#issuecomment-2294793097_

> * [x] [Migration details table colors, tooltips and visibility](https://github.com/conda-forge/conda-forge.github.io/pull/2090#issuecomment-1979121823):
> * [x] https://github.com/conda-forge/conda-forge.github.io/pull/2239

I commented on the colour scheme changes [elsewhere](https://github.com/conda-forge/conda-forge.github.io/issues/2243#issuecomment-2266260967) already, but I wanted to reiterate here that I don't see how various shades of grey are more accessible (e.g. for vision-impaired people)


than the much more distinct colours we had previously


I picked the colours from the bubbles[^1] and [put them](https://www.aremycolorsaccessible.com/palette?colors=%23648e66&colors=%238d949e&colors=%23ccd0d5&colors=%23ebedf0&colors=%23ffb74d&colors=%23fb565b) into aremycolorsaccessible (found by random googling as I was looking for turbo, more below), and while I can't vouch for their methodology, it has pretty clear opinions:


I'm certainly not a web developer, nor expert for UX and accessibility, but I do remember how google [developed](https://research.google/blog/turbo-an-improved-rainbow-colormap-for-visualization/) a new colormap (called "turbo") with accessibility in mind a while back, and naïvely taking that as a reference would seem like we should if anything have starker colours rather than more subdued ones:


Taking the values {0.0, 0.2, 0.4, 0.6, 0.8, 1.0} from their colourmap would give us 6 colours that are in some ways ideally spaced across various metrics (e.g. across various vision impairments, for details see article).

[^1]: because it's hard for me to tell where e.g. `--ifm-color-emphasis-600` is actually defined; some colours are defined in [`custom.css`](https://github.com/conda-forge/conda-forge.github.io/blob/main/src/css/custom.css), but not all