[Bug] Campus Leads don't get success notification when creating new members

[urmade]

Describe the bug
When a campus lead tries to create a new user account, the loading UI triggers but then doesn't switch to the success UI. The account is created in the backend, but the lead gets indicated that the operation didn't finish as the load UI doesn't change.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'commasto-dev.campus-community.org/leads'
2. Click on 'Create new member account'
3. Fill in First name, Last name and Alternative mail address
4. Click on 'Add member'
5. See error

Expected behavior
After adding a new member, the load UI should switch to a 'Success' UI.

Screenshots
Success UI: