smoother handling of expired sessions

[max-nextcloud]

Is your feature request related to a problem? Please describe. If I open a text file and revert it to an old version I see a message asking me to reload.

Describe the solution you'd like I would want text to reconnect to the server and fetch the updated document.

Additional context #6918 turned this from a 409 into a 404 scenario. Now we only need to make that work smooth.