Flaky scans on bulk upload of many files

[lennartdohmann]

Steps to reproduce

1. Set up Nextcloud with G DATA Antivirus app installed and ready to scan
2. Upload files via the UI -> Select many files at once
3. Some will be scanned, some not, sometimes a file is tagged Unscanned

Expected

1. Set up Nextcloud with G DATA Antivirus app installed and ready to scan
2. Upload files via the UI -> Select many files at once
3. All files are uploaded and processed with a verdict

The problem must lie somewhere in the FileEventsListener, which probably has problems with events during a bulk insert.