fix: a11y omnibus package

[werdnanoslen]

Summary

Fixes a bunch of a11y issues that Playwright surfaced (322 of 553 tests failed):

Source changes:

• Required aria-hidden or aria-label or aria-labelledby on all Icons, defaulting to the former being true in storybook. Removed part of a test to this end.
• Changed CardHeader element from header to div to avoid a11y issues that Storybook helpfully demonstrated, and it's how USWDS implements it anyway (probably for the same reason). This might be breaking in case anyone used css to target the rendered semantic header element. If so, please mark as breaking.
• Hid Pagination, SocialLinks, and SearchButton's decorative svgs from screen readers
• Replaced presentation role with aria-label to fix a11y issue, and per USWDS implementation
• Used aria-controls on LanguageSelector only if specified, and for this component only uses it when appropriate

Storybook-only changes:

• Added labels to all DatePicker, InputPrefix, InputSufffix, RangeInput, Select, Textarea, and TextInput stories to fix a11y warnings there, and tidied up a bit
• Changed Tag story colors to meet contrast requirements
• Hid IconList icons from screen readers
• Changed Footer's h3s to ps since class already handled styling and use of a heading seemed unwarranted
• Tidied Pagination's stories
• Disabled 'skip-link' rule for ExtendedNav due to false-positive in Storybook

Related Issues or PRs

Resolves #2811 Resolves #2809

How To Test

If you have Playwright installed locally, run yarn test-storybook. Otherwise, check the Accessibility tab of all the stories

Screenshots (optional)

[werdnanoslen]

~FYI everything is passing checks except for the a11y CI step I added, because it can't run here 🙃 Sooo, maybe we shouldn't run this as a storybook test runner, since it requires a deployed storybook (sorta like how USWDS does it on their PRs). Thoughts on whether to merge this as just a11y updates, with an alternative CI for a11y, or can we still make this work?~

Nvm, I booted it to another branch/PR

[kleinschmidtj]

yarn test-storybook

@werdnanoslen I looked at the code and it looks good to me. I just wanted to run this testing command, but I don't see it the command in package.json. Is this new? Should this have been added as a new script?

[werdnanoslen]

yarn test-storybook

@werdnanoslen I looked at the code and it looks good to me. I just wanted to run this testing command, but I don't see it the command in package.json. Is this new? Should this have been added as a new script?

oh whoops, I'll remove it. I started this ticket by seeing if we should run playwright as a GH task, but I didn't figure out how and pivoted to just fixing the issues it found from running locally.