Update Fund for EditEngine
Summary: Ref T12685, updates fund for edit engine.
Test Plan: Create a Fund, Edit a Fund, wipe out Merchants, check errors for name and missing merchants, back Fund.
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin
Maniphest Tasks: T12685
Differential Revision: https://secure.phabricator.com/D17855