Accessibility: Remove unnecessary ARIA

[cjcenizal]

Some ARIA usage enhances accessibility, but there is also unnecessary and incorrect ARIA. According to the W3C, the first rule of ARIA is: "If you can use a native HTML element [HTML5] or attribute with the semantics and behavior you require already built in, instead of re-purposing an element and adding an ARIA role, state or property to make it accessible, then do so." (http://www.w3.org/TR/aria-in-html/#first-rule-of-aria-use).

Native HTML elements support standard keyboard interactions by default, reducing the amount of scripting needed for custom elements. Incorrect use of ARIA is also a failure of the fourth principle of WCAG 2.0—Robust (specifically Success Criterion 4.1.2).

We should audit Kibana, app by app, and check that each instance of aria- attributes has been applied correctly. We should also update this issue with examples of incorrect ARIA use as they're found, so we can start to identify common anti-patterns,.

[timroes]

Checked all possible aria- attributes that could have been also native attributes, but it seems we are not having any unnecessary ARIA (anymore).