Shall we show the network state in sidebar?

This problem has a long history.

Related posts in the forum and GitHub issue
Related code

I got the idea that some network errors are temporary, hiding them from the sidebar is reasonable.
However, the current version doesn't show most of the network errors at all. If the phone doesn't have the network connection and the user doesn't realize this, he/she will think the sync is completed from the message of the side bar.
Can we test the network connection to the sync target before sync? If Joplin just can't connect to the sync target, then user should get a message in the side bar. I think this solution covers most of the cases when users think they are misled by the Completed message in sidebar.