Final call: ARIA props permitted, make examples compliant with ARIA 1.2 #1372

Hey folks,
Taking this one over from Jean-Yves, who is on vacation.

This PR removes a passed example that is invalid for ARIA 1.2, and updates
another to be valid ARIA 1.2. This final call lasts until August 2nd. If
you have any comments, leave a review on the pull request:

https://github.com/act-rules/act-rules.github.io/pull/1372

Kind regards,

-- 
*Wilco Fiers*
Axe for Web product owner - Co-facilitator WCAG-ACT - Chair ACT-R