Clean up UI spacing/fallbacks in Durable Column Header
Summary: Correct minor spacing issues, makes long Conpherence Titles fallback to ellipsis when overflow. Fixes T7541
Test Plan:
Test a long and short title Conpherence.
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T7541
Differential Revision: https://secure.phabricator.com/D12048