R1:f7290bbbf220

Update a straggling "getAuthorities()" call in Fund

Summary: Ref T13366. The "authorities" mechanism was replaced, but I missed this callsite. Update it to use the request cache mechanism.

Test Plan: As a user without permission to view some initiatives, viewed a list of initiatives.

Maniphest Tasks: T13366

Differential Revision: https://secure.phabricator.com/D20783