fix(popover): temporarily disable intermittent popover test case

[Coread]

The new popover test cases for isContained that I added recently have a case which has an intermittent failure in the percy tests. Until it can be fixed I'm disabling it so it doesn't break the build.

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots:

Before (If applicable):

After:

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

Merging #871 (a831e33) into master (e5f26e9) will increase coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #871      +/-   ##
==========================================
+ Coverage   94.14%   94.20%   +0.06%     
==========================================
  Files         131      131              
  Lines       16371    16371              
  Branches     2403     2407       +4     
==========================================
+ Hits        15412    15422      +10     
+ Misses        959      949      -10     

Impacted Files	Coverage Δ
web-components/src/components/icon/Icon.ts	78.57% <0.00%> (-4.17%)	⬇️
...components/src/components/datepicker/DatePicker.ts	88.53% <0.00%> (-1.19%)	⬇️
web-components/src/components/button/Button.ts	81.99% <0.00%> (-0.28%)	⬇️
web-components/src/components/menu/MenuItem.ts	98.75% <0.00%> (+1.25%)	⬆️
web-components/src/components/label/Label.ts	100.00% <0.00%> (+2.22%)	⬆️
web-components/src/components/list/ListItem.ts	100.00% <0.00%> (+2.94%)	⬆️
...ponents/src/components/progress-bar/ProgressBar.ts	100.00% <0.00%> (+13.39%)	⬆️

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[paulwitty]

Pushing this so that we don't need to override every single other PR in the future...