Cancellations of tickets will not be confirmed by email

**Describe the bug**
Cancellations of tickets will not be confirmed by email, even if the “notify ticket owner” checkbox is checked
(Alf.io v.2.0-M4-2402-3)

**To Reproduce**
Steps to reproduce the behavior:

1. Go to https://[alfio-instance]/admin/'
2. Choose an event
3. Choose "Categories" > "Tickets"
4. Choose "Remove"
5. Mark the checkbox “notify ticket owner”
6. Click "Confirm Removal"

**Expected behavior**
An email according to the “TICKET_HAS_BEEN_CANCELLED” template should be sent.

**Desktop (please complete the following information):**
- OS: Linux Ubuntu 22.04
- Browser: Firefox 126.0 and Chromium 125.0.6422.60

Best regards, and thanks for all your work!
Gregor