@clayui/css: Add option to customize `.inline-item`, `.inline-item-before`, `.inline-item-after` in `clay-button-variant` and `clay-link` mixins

[pat270]

This will allow configuring the size of icons inside buttons and links as well as adding transitions on hover / focus states.

[github-actions]

This issue has been merged and will be released in DXP at https://issues.liferay.com/browse/LPS-139225