feat(PPDSC-2555): SVG Exporter - Export with CSS vars

[LukeFinch]

PPDSC-2555

What

• Removed the tsx export from svg previewer
• Replaced embedded NewsKit token names with css-variables

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:

[newskit-engineering]

You can preview these changes on:
Documentation Site: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-2555-svg-exporter-css-vars
Storybook: http://ncu-newskit-docs.s3-website-eu-west-1.amazonaws.com/ppdsc-2555-svg-exporter-css-vars/storybook

[Vanals]

Where are the svg-previewer tests gone? 🤔 Could you add them back? I cannot even see them from the list of files deleted. I wonder if is part of the "mess up" when it was being moved to '/tool'. We should have tests in place!. Also we have colors-theme-list.tsx within tests now. I think is shouldn't be there.

IF the tests are disappeared completely you might want to look back in the git hystory

[LukeFinch]

Hmm weird. I'll look into it 👍

[mutebg]

Well done @LukeFinch 👏