Improve error when virus is detected

Check these steps out:

1. Install files_antivirus in the server, and enable it
2. Upload virused file (eicar.com) with the android app

Current:

Notification shows correctly that the virus was detected:

But, the upload list shows only Upload not allowed:

The PUT response is 403 Forbidden with Payload:

<?xml version="1.0" encoding="utf-8"?>
<d:error xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns" xmlns:o="http://owncloud.org/ns">
  <s:exception>OCA\DAV\Connector\Sabre\Exception\Forbidden</s:exception>
  <s:message>Virus Win.Test.EICAR_HDB-1 is detected in the file. Upload cannot be completed.</s:message>
  <o:retry xmlns:o="o:">false</o:retry>
  <o:reason xmlns:o="o:">Virus Win.Test.EICAR_HDB-1 is detected in the file. Upload cannot be completed.</o:reason>
</d:error>

Expected: Both notification and uploads view show the same accurate error. That should the expected behaviour for all errors.

Related: https://github.com/owncloud/icap/issues/21

Reproduce the upload with files_antivirus enabled and eicar.com, then inspect how the Android app handles the PUT 403 response in the uploads view and notification paths. Compare both displays with the response message; done means they show the specific virus error rather than only “Upload not allowed.”