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