docs(PPDSC-2287): Grid layout documentation

[Srinivasan-Ramasamy]

PPDSC-2287

What

1. Grid layout documentation UI - http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-2287-grid-layout-documentation/components/grid-layout/
2. Fix for ‘Grid’ page is also highlighted in the side nav.
3. Stories: Merged part of this story - docs:(PPDSC-2066) grid-layout docs #174.

I have done:

• Written unit tests against changes
• Written functional tests against the component and/or NewsKit site
• Updated relevant documentation

I have tested manually:

• The feature's functionality is working as expected on Chrome, Firefox, Safari and Edge
• The screen reader reads and flows through the elements as expected.
• There are no new errors in the browser console coming from this PR.
• When visual test is not added, it renders correctly on different browsers and mobile viewports (Safari, Firefox, small mobile viewport, tablet)
• The Playground feature is working as expected

Before:

After:

Who should review this PR:

How to test:

URL: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-2287-grid-layout-documentation/components/grid-layout/

[newskit-engineering]

You can preview these changes on:
Documentation Site: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-2287-grid-layout-documentation
Storybook: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-2287-grid-layout-documentation/storybook

[mstuartf]

What does this change do?

[Srinivasan-Ramasamy]

Thanks @mstuartf for reviewing the changes.

Actually this changes wants to avoid the extra empty space below the Accessibility section:

We're conditionally rendering the block to avoid the extra space here:

To match the figma design, we've updated this condition.