Fix an issue with the Spaces EditField not reading values properly

Summary: Fixes T9988. This logic got inverted by accident at some point.

Test Plan:

• Edited a task, shifting spaces.
• Created a task in default space.
• Created a task in custom space.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9988

Differential Revision: https://secure.phabricator.com/D14787