[Redesign] Update Workboards
Summary: Ref T8099, Cleans up Workboard UI, fixes button icon spacing
Test Plan: Review workboards on desktop, mobile
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: epriestley, Korvin
Maniphest Tasks: T8099
Differential Revision: https://secure.phabricator.com/D13473