Make editing project images redirect to "Manage" more consistently

Summary:
Ref T12732. Currently, different ways of setting a profile image can leave you in different places.

Instead, always send the user back to the "Manage" page.

Test Plan: Used "Current Picture", "use picture", "Build picture" and "upload picture", always ended up in the same spot.

Reviewers: chad, amckinley

Reviewed By: amckinley

Maniphest Tasks: T12732

Differential Revision: https://secure.phabricator.com/D17967