Normalize spacing around empty object lists

Summary: Adds an li for semantics, fixes spacing around error view in a phui-box or not

Test Plan: view a project with no tasks, perform a search with no data returned.

Reviewers: epriestley

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8371