R1:f8581f687c9b

Restrict green button to buttons

Summary: Ref T12780. Button styles are bleeding over here on the icon, restrict to .button classes

Test Plan: uiexamples.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T12780

Differential Revision: https://secure.phabricator.com/D18055