No email notification for `File rejected` event

## Describe the bug
Currently, email notification for `File rejected` event is not implemented. So, there's no email notification when a file with virus is uploaded. And we currently don't know if it will be implemented or not in the near future.


## Steps to reproduce
1. Run the server with antivirus service [clamAV](https://owncloud.dev/ocis/development/testing/#running-test-suite-with-antivirus-service-antivirus) and email service [mailpit](https://owncloud.dev/ocis/development/testing/#running-test-suite-with-email-service-email).
2. As user `demo`, upload a file with virus.
3. User `demo` gets in-app notification for virus found.
4. Check for email notification in email service `mailpit`.

## Expected behavior
Expected to get an email notification related to `Virus found` ❓

## Actual behavior
No email notification.

https://github.com/user-attachments/assets/29303e53-943f-4df9-a433-d9d1615d1ec3

## Setup
``` Console
OCIS_LOG_LEVEL=debug \
PROXY_ENABLE_BASIC_AUTH=true \
OCIS_ADD_RUN_SERVICES=notifications \
NOTIFICATIONS_SMTP_HOST=localhost \
NOTIFICATIONS_SMTP_PORT=1025 \
FRONTEND_CONFIGURABLE_NOTIFICATIONS=true \
NOTIFICATIONS_SMTP_INSECURE=true \
NOTIFICATIONS_SMTP_SENDER="owncloud " \
ANTIVIRUS_SCANNER_TYPE="clamav" \
ANTIVIRUS_CLAMAV_SOCKET="tcp://host.docker.internal:3310" \
POSTPROCESSING_STEPS="virusscan" \
OCIS_ASYNC_UPLOADS=true OCIS_ADD_RUN_SERVICES="antivirus" ./ocis/bin/ocis server
```

``` Console
Infinite Scale 7.1.0-rc.5+482bc0cd06 Community
ownCloud Web UI 11.3.0
```