P1 1270 no label formfield a11y

[marijnyoast]

Context

• [UI-Library] Makes sure that users of a screenreader don't potentially miss context on certain Input elements

Summary

All Form field elements should have a Label for screen reader users. This PR ensures that by making the Label required on those Components.

This PR can be summarized in the following changelog entry:

• [@yoast/ui-library] All Form field elements should have a label for screen reader users. The label prop is now required.

Relevant technical choices:

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Open the UI Library Storybook
• Verify the following for all Form elements
  • The Label is required (red asterisk in the Factory)
  • Alle examples have a Label

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo] and I have added test instructions for Shopify.

Documentation

• I have written documentation for this change.

Quality assurance

• I have tested this code to the best of my abilities
• I have added unittests to verify the code works as intended
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.

Fixes P1-1270

[igorschoester]

CR & ACC ✅