R1:ff677c1964b1

Fix two error strings in the diffusion.uri.edit Conduit method

Summary: Fixes T11839. Both are missing a parameter and one is a copy/paste slop.

Test Plan:
{F1913812}

{F1913813}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11839

Differential Revision: https://secure.phabricator.com/D16837