Support Spaces in Maniphest batch editor

Summary: Ref T8498. This editor is an artifact of the Old World at this point, but it still works fine.

Test Plan: Moved tasks between spaces using the batch editor.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T8498

Differential Revision: https://secure.phabricator.com/D13249