What problem does this address?

Given #59514 and the conversation in #59444, I think we should allow theme authors to use theme.json to set specific colors that would be given priority over the fallbacks (text color) and (button color/link color). With the merged PR, my Powder theme will result in this, which is less than helpful.

What is your proposed solution?

Add support in theme.json for something like this:

{
	"settings": {
		"example": [
			{
				"colors": [ "#0a0a0a", "#6d28d9" ]
			}
		]
	}
}

cc: @richtabor @justintadlock @spencerfinnell