Diff change timeline entry on diffs is using an extra container

Summary

Diff change timeline entry on diffs is using an extra container.

Steps to reproduce

Change diff on a branch that is associated with a merge request.

Example Project

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22770/diffs?diff_id=26730664#f175a5afe0abd648c4a9af0d75730f920275bb20_38_30

Relevant logs and/or screenshots