[Redesign] Clean up borders on ObjectItems

Summary: Ref T8099. A wild border appears!

Test Plan: Remove border when barColor is present. Test workboards and Maniphest.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T8099

Differential Revision: https://secure.phabricator.com/D13494