R1:1b8337871b88

Correct the handle URI for build steps

Summary: Fixes T9674. This was wrong to start with (URI is `/edit/X/`, not `/X/edit/`) but we have a new view page anyway.

Test Plan:
- Visited an exmaple URI in my browser.
- Followed a build step link from "Authorized By: ..." in Drydock.

Reviewers: joshuaspence, chad

Reviewed By: chad

Maniphest Tasks: T9674

Differential Revision: https://secure.phabricator.com/D14366