@clayui/css: Sync Clay CSS changes with Cadmin

We've had some changes merged before Cadmin. We need to sync those changes in Cadmin.

https://github.com/liferay/clay/pull/3998
https://github.com/liferay/clay/pull/4002
https://github.com/liferay/clay/pull/4040
https://github.com/liferay/clay/pull/4055
https://github.com/liferay/clay/pull/4056
https://github.com/liferay/clay/pull/4060