Fix navigation flow when refreshing a document after a task completion

Steps to reproduce:

1. Start a Serial workflow
2. Click on the Process button
3. The task is displayed in a left panel
4. Add "Administrator" to the participants and click on the button "Start review"
5. The document is displayed in "full screen"
6. Observe in the address bar that the URL is still a "task" URL like http://localhost:8080/nuxeo/ui/#!/tasks/b591cc6b-8781-4f09-90ef-2451afcce4fa
7. Hit the F5 key to refresh
8. The previously completed task is displayed

Expected behavior: the document is displayed (with the Task panel)