feat(web-components): add additional functionality to existing ic-divider component

[GCHQ-Developer-112]

Summary of the changes

Add props to allow existing ic-divider to be more customisable, add stories & prop playground, add tests, update side navigation test following change to ic-divider

BREAKING CHANGE: Change default styling and props on ic-divider

Related issue

#1331

Checklist

General

• [ ] Changes to docs package checked and committed.
• [ ] All acceptance criteria reviewed and met.

Testing

• [ ] Relevant unit tests and visual regression tests added.
• [ ] Visual testing against Figma component specification completed.
• [ ] Playground stories in React Storybook up to date, with any prop changes and additions addressed.
• [ ] Compare performance of modified components against develop using Performance addon in React Storybook.

Accessibility

• [ ] Accessibility Insights FastPass performed.
• [ ] A11y unit test added and yields no issues.
• [ ] A11y plug-in on Storybook yields no issues.
• [ ] Manual screen reader testing performed using NVDA and VoiceOver.
• [ ] Manual keyboard testing for keyboard controls and logical focus order.
• [ ] Correct roles used and ARIA attributes used correctly where required.
• [ ] Logical heading structure is maintained, and the HTML elements used for headings can be changed to fit within the wider page structure.

Resize/zoom behaviour

• [ ] Page can be zoomed to 400% with no loss of content.
• [ ] Screen magnifier used with no issues.
• [ ] Text resized to 200% with no loss of content.
• [ ] Text spacing increased as per the WCAG 1.4.12 success criterion with no loss of content.

System modes

• [ ] Browser setting 'prefers reduced motion' tested. No animations or motion visible whilst this setting is on.
• [ ] Windows High Contrast mode tested with no loss of content.
• [ ] System light and dark mode tested with no loss of content.
• [ ] Browser support tested (Chrome, Safari, Firefox and Edge).

Testing content extremes

• [ ] Min/max content examples tested with no loss of content or overflow.
• [ ] All prop combinations work without issue.
• [ ] Tested for FOUC (Flash of Unstyled Content) in both SSR (Server-Side Rendering) and SSG (Static Site Generation) settings.
• [ ] Controlled and uncontrolled input components tested.
• [ ] Props/slots can be updated after initial render.

[github-actions[bot]]

View your branch deployment here: https://mi6.github.io/ic-ui-kit/branches/1331-divider-component-new/web-components View your React branch deployment here: https://mi6.github.io/ic-ui-kit/branches/1331-divider-component-new/react

[github-actions[bot]]

Cypress visual tests failed. View the image diff here: https://github.com/mi6/ic-ui-kit/tree/gh-pages/branches/1331-divider-component-new/cypress-image-diff-screenshots/diff View the html report here: https://mi6.github.io/ic-ui-kit/branches/1331-divider-component-new/cypress-image-diff-html-report/cypress-image-diff-html-report.html