Fix MR closed icon
Similar to #325588 (closed), the MRs closed icon in their header on smaller viewports is not the same as the issue's closed icon or for closed MRs shown in issues:
| Current icon | Correct icon |
|---|---|
 |
 |
Similar to #325588 (closed), the MRs closed icon in their header on smaller viewports is not the same as the issue's closed icon or for closed MRs shown in issues:
| Current icon | Correct icon |
|---|---|
|
|