[Woo POS] Replaces the custom colors with the once from the palette

[backwardstruck]

From @kidinov here:

Create a ticket to replaces the custom colors with the once from the pallite, because I think we probably use slightly wrong variations, for instance primary colors is probably WooPurple50 which is not 9C70D3

[dangermattic]

🚫 Please add a type label (e.g. type: enhancement) and a feature label (e.g. feature: stats) to this issue.