fix: padding fixes for uui-combobox

[enkelmedia]

Fixing padding according to this issue: #666

Before and after:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
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Checklist

• If my change requires a change to the documentation, I have updated the documentation in this pull request.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[github-actions]

Hi there @enkelmedia, thank you for this contribution! 👍

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[iOvergaard]

LGTM. Thanks!