kcms/colors: enable accent color from wallpaper by default
I seem to recall this was one of the proposed and accepted Plasma 6 proposals but I can't find an issue for it. Anyway, here is the doing it.
This change does not mean we will no longer use Breeze Blue with our default wallpapers.
If we decide to use the automatic extraction algorithm with our default wallpapers, we don't know yet what this will look like with all-defaults on Plasma 6 since that will depend on the yet to be selected wallpaper.
However it is possible to specify an explicit accent color to use for the wallpaper if we don't like the one determined by the automatic extraction algorithm.
We could even go with just Breeze Blue, and only once the user chooses a custom wallpaper they will get a non-default accent color to match it.
And if we still find it's no good, it is easy enough to (and I would be fine with) revert this later, as it's no more than a one-line change of defaults.