Update tracking prompt accessibility

[nylen]

Fixes #2215.

• Remove the default notice dismissal behavior for this notice
• Move the control buttons in the editor tracking prompt to after the content
• Move the clarification message behind a "More info" button and a Popover component
• Add focus styles and any needed aria attributes for the "More info" button

edit: outdated screenshots removed; see below

[codecov]

Codecov Report

Merging #2217 into master will increase coverage by 0.82%.
The diff coverage is 71.42%.

@@            Coverage Diff             @@
##           master    #2217      +/-   ##
==========================================
+ Coverage   22.99%   23.81%   +0.82%     
==========================================
  Files         141      142       +1     
  Lines        4393     4531     +138     
  Branches      746      771      +25     
==========================================
+ Hits         1010     1079      +69     
- Misses       2852     2904      +52     
- Partials      531      548      +17

Impacted Files	Coverage Δ
editor/actions.js	37.93% <0%> (-1.36%)	⬇️
editor/index.js	0% <0%> (ø)	⬆️
editor/enable-tracking-prompt/index.js	87.5% <83.33%> (-12.5%)	⬇️
blocks/library/heading/index.js	20.83% <0%> (-2.98%)	⬇️
blocks/library/quote/index.js	13.55% <0%> (-0.73%)	⬇️
blocks/api/paste/strip-attributes.js	0% <0%> (ø)	⬆️
blocks/api/paste/convert-tables.js	0% <0%> (ø)
blocks/api/paste.js	61.53% <0%> (+1.53%)	⬆️
blocks/library/pullquote/index.js	35.71% <0%> (+2.38%)	⬆️
... and 1 more

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[afercia]

I'd move the popover out from the button and use aria-expanded on the button based on the showInfoPopover state. See for example post-visibility.

[nylen]

I think then we need another container element with position: relative to hold the button and the popover.

[afercia]

Yep, I think that's the reason why a wrapper element was added around button and popover in the post-visibility.

[afercia]

Thanks @nylen ! just a coupe small things.

[nylen]

Feedback addressed; focus styles added:

Note that the Popover renders as a div, so it cannot be a child of a p element. Otherwise, the following React warning occurs:

Warning: validateDOMNesting(...): <div> cannot appear as a descendant of <p>.

[afercia]

Thanks!