Associate FormControl.Validation with the relevant input

[joshfarrant]

Summary

Adds the FormControl.Validation component's id to the FormControl input's aria-describedby to help assistive tech understand the relationship between the input and the validation message.

List of notable changes:

• Adds aria-describedby to FormControl input for FormControl.Validation component
• Adds tests for FormControl.Validation association with the input
• Adds missing tests for FormControl.Hint association with the input

What should reviewers focus on?

• Check that you can see the aria-describedby association in the HTML
• Bonus points for testing with a screen reader

Supporting resources (related issues, external links, etc):

• Closes https://github.com/github/primer/issues/3780

Contributor checklist:

• All new and existing CI checks pass
• Tests prove that the feature works and covers both happy and unhappy paths
• Any drop in coverage, breaking changes or regressions have been documented above
• UI Changes contain new visual snapshots (generated by adding update snapshots label to the PR)
• All developer debugging and non-functional logging has been removed
• Related issues have been referenced in the PR description

Reviewer checklist:

• Check that pull request and proposed changes adhere to our contribution guidelines and code of conduct
• Check that tests prove the feature works and covers both happy and unhappy paths
• Check that there aren't other open Pull Requests for the same update/change

Screenshots:

Please try to provide before and after screenshots or videos

Before	After

[changeset-bot]

🦋 Changeset detected

Latest commit: bbb49b5

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 6 packages

Name	Type
@primer/react-brand	Patch
@primer/brand-primitives	Patch
@primer/brand-e2e	Patch
@primer/brand-fonts	Patch
@primer/brand-config	Patch
@primer/brand-storybook	Patch

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[github-actions]

🟢 No design token changes found

[github-actions]

⚠️ Visual differences found

Our visual comparison tests found UI differences.

Please review the differences by using the test artifacts to ensure that the changes were intentional.

Artifacts can be downloaded and reviewed locally.

Download links are available at the bottom of the workflow summary screen.

Example:

If the changes are expected, please run npm run test:visual:update-snapshots to replace the previous fixtures.

Review visual differences

[rezrah]

🙌 nice! thanks @joshfarrant, ship it