bug(material/list): selected state is visually communicated only with color (WCAG 1.4.1)

[zarend]

Description

single-select list visually communicate selected state with color alone. It should be visually communicated with more than just color.

https://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-without-color.html

Reproduction

1. open https://material2-dev.web.app/list
2. Navigate to "Single Selection list" demo
3. Under "Favorite Grocery", click "Oranges"

Expected Behavior

selected state of "Oranges" is visually communicated with more than color alone

Actual Behavior

color of "Oranges" changes to indicate selected state