Always return MR diff_refs if importing
What does this MR do?
This MR fixes a bug that prevented project import with diff notes in merge requests to be fully migrated. Merge requests in the migrated project would not be shown.
More details in: https://gitlab.com/gitlab-org/gitlab-ce/issues/63955
Does this MR meet the acceptance criteria?
Conformity
Edited by George Koltsov