feat: Update spacing in Ordered and Unordered List

[dlnr]

Describe the pull request

While synchronizing figma variables with tokens the lack of space above a sublist became apparent. UX suggested the same amount of padding as the gap but didn't consider the line-height of the items. So I went with xs, and now it is visualy a little bit closer to the parent.

What

A rule for padding and a token for the child list of a ul or ol.

Why

It was cramped.

How

Just some CSS

Checklist

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• Add or update unit tests
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Additional notes

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[VincentSmedinga]

We’re also considering adding some whitespace at the bottom of the nested list. This PR can await that decision.

[VincentSmedinga]

We’ve increased the space between items at level 1 to ams-space-md and applied the ams-space-sm to level 2.

I’ve added padding-block-end tokens for teams that want to reuse our list component.