Fix Column Edit URI, simple dropdown UI

Summary: Fix the URL to editing columns, fix the color of a PHUIX dropdown(simple)

Test Plan: Click on Dropdown, don't feel offended. Edit a Column from various search URLs. Fixes T5341

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T5341

Differential Revision: https://secure.phabricator.com/D9507