R1:33e9033b99f3

Fix white corner bleed on workcards

Summary: There is a hair of #fff hanging out on the right side, round it a bit.

Test Plan: ZOOOOM IN on a Workboard

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D15138