fix(tooltips): fix rendering stutter in Safari

[austingreendev]

Description

Since tooltips was one of our first usages of Popper.js the visibility logic was slightly different than Menus, Select, and other usages within the codebase. This difference causes a stutter effect for some renderings in Safari.

Detail

Previously, we handled visibility with a custom aria-hidden value to toggle the visibility on/off. This was originally for an accessibility requirement that was shown to not be needed in the recent Axe/Lighthouse walkthrough that I recently completed.

This PR:

• Toggles visibility with a ternary rather than a css:hidden trick
• Adds accessibility changes that was originally surfaced in [ACCESSIBILITY] Global changes to pass AXE/Lighthouse Audits #66
• Updates tests to work with new logic

Thanks @zillding for finding this one!

Checklist

• 👌 design updates are Garden Designer approved (add the
  designer as a reviewer)
• 💅 view component styling is based on a Garden CSS
  component
• 🌐 Styleguidist demo is up-to-date (yarn start)
• ⬅️ renders as expected with reversed (RTL) direction
• 💂‍♂️ includes new unit and snapshot tests
• 📒 any new files are included in the packages src/index.js export
• 📝 tested in Chrome, Firefox, Safari, Edge, and IE11

[zillding]

👍 code looks fine.

as long as it works across browsers.

💯

[coveralls]

Pull Request Test Coverage Report for Build 477

• 3 of 3 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.005%) to 96.169%

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Totals
Change from base Build 468:	0.005%
Covered Lines:	1692
Relevant Lines:	1706

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💛 - Coveralls

[austingreendev]

as long as it works across browsers

Tested and working as expected without a stutter in all browsers