Cannot download the preview of password protected link shared file using basic auth

## Steps to reproduce
1. Create a password protected link share of a file (`lorem.txt`)
2. Try to download the preview
```bash
# with remote.php
curl 'https://localhost:9200/remote.php/dav/public-files/YMYxKFSIDBqROug/lorem.txt?preview=1' \
-u public:strong-pass -vk

# without remote.php
curl 'https://localhost:9200/dav/public-files/YMYxKFSIDBqROug/lorem.txt?preview=1' \
-u public:strong-pass -vk
```
```xml
< HTTP/1.1 404 Not Found
< Content-Type: application/xml; charset=utf-8
...

Sabre\DAV\Exception\NotFound
File with name lorem.txt could not be located

```

## Related issues
- https://github.com/owncloud/ocis/issues/8602