Updated action buttons for components and static pages 

Updates the component header for units in preparation for the addition of the move and a/b content testing stories, as well as to visually clean up the older button styles on these two pages. 

A follow on story will be to document, define, and standardize our visual approach to action buttons, though this will land in a separate pull request. 

@talbs, @frrrances - If someone could review this to double check button appearances throughout studio, as well as make any other FED suggestions that would be great. thanks!