Don't show a notification for an upload that failed because of network issues/automatic uploads

There already is a lot of opened issues about the convergence of (failed) uploads and notifications.

My personal usecase is automatic uploads of pictures I take, most of the time offline, that I then want uploaded to some directory when I get online. I don't use manual uploads.

What happens in practice is that for each photo I take nextcloud randomly tries to upload it and of course it fails when I'm offline and shows me a notification. Somehow it doesn't learn from its mistake and on the next photo it tries again.

I don't have big solutions and it's obviously being worked on, but I think there are some ways to make it a bit more bearable without big changes:

- if it is possible to detect that the issue is the lack of network, don't show a notification. I know it won't work
- if it is an automatic upload, don't show transient failures: I expect the upload to _eventually_ work, if it takes more time it takes more time and that's fine