Widen property list key value

Summary: Ref T12180. Seems we widened the value side, but not the key.

Test Plan: Review application property page. Set item to stacked, see non-cutoff layout.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T12180

Differential Revision: https://secure.phabricator.com/D17302