xml files don't have a priview/icon

[individual-it]

Steps to reproduce

1. upload a .xml file

Expected behaviour

some kind of icon like other files

Actual behaviour

Tell us what happens instead

[fschade]

needs to be discussed if this makes sense, at the moment we support thumbnails for txt files, so in my opinion nothing speaks against it. cc @kulmann

[kulmann]

The issue here was that xml files had neither (not a preview and not a generic icon for the file type). Has been fixed with #4357

See screenshot:

If xml files should have previews is a decision for the thumbnail service in ocis, not a web issue.