feat(PPDSC-2859): use newskit-website theme from publisher

[LukeFinch]

PPDSC-2859

What

Background - why this is needed
Uses themes from the newskit-themes-publisher repo for the docs site.

What did you do

• Import website themes from the publisher
• Remove old website themes data
• Update tests, we no longer need to check for overrides, as they are contained in the theme package
• Changed some on-site components to line up with expectations from design

What does the reviewers should expect
Design changes have been manually checked and approved
Snapshot updates are mostly due to px changing to rem & hex codes coming in lower case
I've removed a test

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:

[pp-serviceaccount]

You can preview these changes on:
Documentation Site: http://ncu-newskit-docs-pr.s3-website-eu-west-1.amazonaws.com/ppdsc-2859-use-theme-from-publisher
Storybook: http://ncu-newskit-docs-pr.s3-website-eu-west-1.amazonaws.com/ppdsc-2859-use-theme-from-publisher/storybook

[Vanals]

Should you make ticket for this? in case we forget?
Sounds an extra good step for testing how user would implement it.

Even if, in this scenario I think we do not need to specify newskitLight as it is the default base theme inside the function, am I wrong?

[LukeFinch]

Will add it to the backlog 👍

[Vanals]

Left a few comments but the rest looks good. If wasn't checked already could you also double check the SVG Previewer is behaving as expected? it uses all the doc site theme to preview the SVGs. It should correctly import and use the themes for displaying the SVG.
See colors-theme-list.tsx

[LukeFinch]

Left a few comments but the rest looks good. If wasn't checked already could you also double check the SVG Previewer is behaving as expected? it uses all the doc site theme to preview the SVGs. It should correctly import and use the themes for displaying the SVG. See colors-theme-list.tsx

good callout - I will double-check.
In theory - if it's importing the exports from docs-theme.ts it should be fine

[Vanals]

LGTM