Changeset 48277 for trunk/src/wp-admin/css/colors/modern/colors.scss

Color schemes: Add new modern color scheme option.

This PR adds a new color scheme option, which uses a high luminosity blue spot color, almost-black menu, and pure white for menu items.
This helps increase contrast, and bring more consistency with some of the higher contrast colors used in the block editor.

Props joen, ibdz, shaunandrews.
Fixes #50504.