[Docs] Fix spacing of code blocks in lists

[tkajtoch]

Describe the bug

The new documentation site renders code blocks in list items with no margin between the list item text content and the code block. This leads to the content being slightly less readable and not matching the site's look and feel. It appears that different margins are applied to the first and subsequent code block elements.

Impact and severity

All content is rendered and readable. The presentation needs improvement.

To Reproduce

Go to https://eui.elastic.co/pr_8741/docs/developer-guides/emotion/migrating-from-sass/#performing-math-on-size-tokens

Expected behavior

The code blocks and list items should be spaced accordingly

Screenshots

[github-actions]

👋 Hi there - this issue hasn't had any activity in 6 months. If the EUI team has not explicitly expressed that this is something on our roadmap, it's unlikely that we'll pick this issue up. We would sincerely appreciate a PR/community contribution if this is something that matters to you! If not, and there is no further activity on this issue for another 6 months (i.e. it's stale for over a year), the issue will be auto-closed.