R1:03ddb4a0fcec

Add slug check around project.query conduit call

Summary: Fixes T6252

Test Plan: Test project query from conduit app, see no errors in log.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6252

Differential Revision: https://secure.phabricator.com/D10655