Add button style guidance to empty states
Problem to solve
In gitlab-org/gitlab#289295 (closed) I'm trying to get the Secure & Protect empty states aligned and I realized there's no mention of which button color to use (green or blue) in the empty state Pajamas docs. This has led to inconsistencies in empty state button styles across the product.
Proposed solution
Add guidance for button style to the Empty states page (in the Call to action point under Usage) in the Pajamas documentation.