Fix go generate lint
Created by: efritz
https://github.com/sourcegraph/sourcegraph/pull/27997 added a mock that wasn't covered in ecda8d8c663cdbde169c2bd48d9400e0edf88474.
Created by: efritz
https://github.com/sourcegraph/sourcegraph/pull/27997 added a mock that wasn't covered in ecda8d8c663cdbde169c2bd48d9400e0edf88474.