Use phutil_utf8_shorten() in PhabricatorProjectListController

Summary: This is a little cleaner and more general than textWrap(). See also
D559.
Test Plan: Loaded project list page, edited a project description to have >100
characters of text, reloaded list page, it was correctly shortened.
Reviewed By: tuomaspelkonen
Reviewers: cadamo, jungejason, aran, tuomaspelkonen
CC: aran, tuomaspelkonen
Differential Revision: 584