[Selectable tile] The checkmark bx--tile__checkmark is barely visible for high contrast mode users because it does not maintain a 3:1 contrast ratio

[cheer021]

Environment

Operating system

Windows

Browser

FF (should be across browsers)

Automated testing tool and ruleset

Assistive technology used to verify

Detailed description

What version of the Carbon Design System are you using?
latest

What did you expect to happen?
maintain a 3:1 contrast ratio

What happened instead?
does not maintain a 3:1 contrast ratio

What WCAG 2.1 checkpoint does the issue violate?

maintain a 3:1 contrast ratio

Steps to reproduce the issue

1. On your Windows machine, turn on High Contrast # 2 theme
2. Browsing on Firefox ESR
3. single-click on a tile to select it
4. Look at the checkmark that shows

Additional information

• reported by our QCs:

All icons in Cognos Analytics should adhere to the IBM Accessibility Checklist's minimum contrast ratio

[tw15egan]

Should be resolved via #8489