remove link to sunset resource on accessibility.mdx (#41418)

Author: crgrafton

site/src/content/docs/getting-started/accessibility.mdx

@@ -52,7 +52,6 @@ On browsers that support `prefers-reduced-motion`, and where the user has *not*
 - [Web Content Accessibility Guidelines (WCAG) 2.2](https://www.w3.org/TR/WCAG/)
 - [The A11Y Project](https://www.a11yproject.com/)
 - [MDN accessibility documentation](https://developer.mozilla.org/en-US/docs/Web/Accessibility)
-- [Tenon.io Accessibility Checker](https://tenon.io/)
 - [Color Contrast Analyser (CCA)](https://www.tpgi.com/color-contrast-checker/)
 - ["HTML Codesniffer" bookmarklet for identifying accessibility issues](https://github.com/squizlabs/HTML_CodeSniffer)
 - [Microsoft Accessibility Insights](https://accessibilityinsights.io/)