R1:07f1a03262d5

Fix a bad call when prefilling ApplicationSearch from `?projects=some_slug`

Summary: Fixes T10299.

Test Plan:
- Visited `/maniphest/?projects=x` locally, where `x` is some valid project slug.
- Before patch: Fatal on `requireViewer()` call.
- After patch: Works correctly, filling the correct project into parameters.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10299

Differential Revision: https://secure.phabricator.com/D15214