Fix workboard link from project profile pages
Summary: Fixes T5165. This uses $this->id, but that may not always be populated anymore. Use the project ID directly instead.
Test Plan: Clicked a workboard link.
Reviewers: btrahan, chad
Reviewed By: chad
Subscribers: epriestley
Maniphest Tasks: T5165
Differential Revision: https://secure.phabricator.com/D9266