Bugfix: Do not load files from cache in public links

When apps (i.e Drawio) try to load a file, the browser caches the request.
If the file was modified somewhere else, this causes inconsistent results which prevent saving any changes until the cache is properly cleared.
This had previously been fixed for normal files, but not yet for public links - which we took care of now.

https://github.com/owncloud/web/pull/7811
https://github.com/owncloud/web/pull/7075
