Fix getIcon calls in PHUIObjectListItem

Summary: Fixes T11501. Let's you pass in a full PHUIIconView or just the icon name to give ObjectListItem a large icon.

Test Plan: Alamanac, Applications, Drydock, Settings, Search Typeahead, Config page...

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, PHID-OPKG-gm6ozazyms6q6i22gyam

Maniphest Tasks: T11501

Differential Revision: https://secure.phabricator.com/D16421