[2.1] Update Gutenberg packages

[pierlon]

Summary

Initially this PR started off with updating the @wordpress/components package to the first version that would have the CSS necessary to fix the issue reported in #6235 (comment), but that later meant the other Gutenberg packages had to also be updated to prevent any breaking changes between them since they rely on each other. Updating those packages then affected some JS/CSS tests and prevented the project from being built, so I ultimately decided to update the set of Gutenberg packages to match the ones on the develop branch, while also cherry-picking some changes along the way that would fix those tests and build errors.

One benefit from these set of changes is that this branch should be more compatible with the latest version of Gutenberg and should reduce any likeliness of any UI/UX regressions we would expect on the develop branch.

Fixes #6235

Checklist

• My code is tested and passes existing tests.
• My code follows the Engineering Guidelines (updates are often made to the guidelines, check it out periodically).

[codecov]

Codecov Report

Merging #6585 (cd561da) into 2.1 (4205e6e) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##                2.1    #6585      +/-   ##
============================================
- Coverage     75.74%   75.73%   -0.02%     
  Complexity     5925     5925              
============================================
  Files           237      237              
  Lines         17942    17942              
============================================
- Hits          13590    13588       -2     
- Misses         4352     4354       +2     

Flag	Coverage Δ
javascript	78.86% <100.00%> (-0.26%)	⬇️
php	75.59% <ø> (ø)
unit	75.59% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
assets/src/block-editor/helpers/index.js	39.28% <ø> (ø)
...block-validation/components/error/error-content.js	93.54% <ø> (ø)
...k-validation/components/error/error-panel-title.js	100.00% <ø> (ø)
...sets/src/block-validation/components/icon/index.js	100.00% <ø> (ø)
...alidation/components/sidebar-notification/index.js	100.00% <ø> (ø)
...dation/components/with-amp-toolbar-button/index.js	100.00% <ø> (ø)
...dation/hooks/use-validation-error-state-updates.js	85.07% <ø> (ø)
assets/src/common/helpers/index.js	91.22% <ø> (ø)
assets/src/components/amp-drawer/index.js	73.07% <ø> (ø)
assets/src/components/amp-info/index.js	100.00% <ø> (ø)
... and 14 more

[github-actions]

Plugin builds for cd561da are ready 🛎️!

• Download development build
• Download production build

[westonruter]

Looking good! With 2.1.4-alpha vs 2.1.4-alpha-20210831T011634Z-cd561dafb:

Before	After

And it looks the same with Gutenberg deactivated.

[pierlon]

For QA I think we should test the minimum version of WP we're supporting for dependencies:

amp-wp/src/DependencySupport.php

Line 33 in 2607345

const WP_MIN_VERSION = '5.6';