Fix height of DarkConsole request log
Summary: When I have displayed DarkConsole and write a comment it keeps scrolling because new AJAX requests pop up.
Test Plan: Displayed it, issued couple of AJAX requests.
Reviewers: btrahan, epriestley
Reviewed By: epriestley
CC: aran, Korvin
Maniphest Tasks: T1316
Differential Revision: https://secure.phabricator.com/D3605