[VSM] Duplicated event on stage form

How to reproduce:

1. Open group VSM.
2. Click add stage.
3. Select 'Issue Created' as start event.
4. Open end event dropdown, you'll see two Issue first mentioned in commit.

The backend sends unique events so I think the duplication is introduced on the FE side. Since the event id is the same, it's not going to cause trouble on the BE, it's just a visual issue.