Improve "Updating failed. You are probably offline." error message to be more specific and actionable

[annezazu]

At varying points, we've all run into the dreaded "Updating failed. You are probably offline." message:

This error message in general isn't quite actionable or clear so I wanted to open an issue to brainstorm how it can be improved and collect some feedback. This is especially relevant when we think about phase 3 and future collaboration. This builds upon prior related issues like #6322 and #4590 where better autosaving was implemented.