KSES: Add selected ARIA attributes support.

Allow low-privileged users to use the ARIA attributes `aria-describedby`, `aria-details`, `aria-label`, `aria-labelledby` and `aria-hidden`.

Merges [43731] to trunk.

Props mattheu, swissspidy, rianrietveld, afercia, GaryJ.
See #30421.

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git-svn-id: https://core.svn.wordpress.org/trunk@43816 1a063a9b-81f0-0310-95a4-ce76da25c4cd