Block switcher icon no longer overrides custom background color

[sabernhardt]

The block-switcher stylesheet no longer has a background color for block switcher icons in the disabled state.

PR #16390 added a gray background color to make sure the dark icon color had contrast, and then #19344 removed the light background.

Original report by @dingo_d on Trac

In the wp-includes/css/dist/block-editor-style.min.css there is a
.components-button.block-editor-block-switcher__no-switcher-icon:disabled .block-editor-block-icon.has-colors{color:#1e1e1e!important}

Which turns all the icons in the editor for blocks black (dark gray). Not sure why, as I don't see this in the GB on github 🤷🏼‍♂️

This is grating because when you are building your own blocks and icons, they are turned black, even though you set the color to be white for instance (when you want to switch one block to another).

We have fills in the icons set to currentColor so that the background of the icon can come through and it looks seamless in the block picker.