Should network offline diagnostic be refreshed automatically

[jandubois]

The network offline checks used to be triggered by events, but this only worked when the used switched pages.

This has been "fixed" by #2972 and the corresponding PR.

Since the network status can change at any time, the diagnostic is more useful when it triggers automatically than if the user has to manually "Re-run" all diagnostics.

It is however confusing if some diagnostics update automatically and others don't.

We need to figure out what to do for the best user experience!