Sync without changes takes 6-9 seconds on desktop

During testing the PR that speeds up sync on Linux I also noticed that a normal sync (without any changes) takes 6-9 seconds.

This is really bad perfomance-wise. Especially since this only took around 2 seconds half a year ago.

I think it’s important we figure out why that is and where the time is lost. A few requests to a WebDAV server can’t take that long. Maybe there’s a way to optimize this process.