Flatpaks should be updated daily
In previous versions of gnome-software, Flatpak updates were automatically installed daily. Since 40, it seems that's no longer the case, probably due to #947 (closed).
The goal in #947 (closed) was to reduce the frequency with which we nag users about non-critical updates. However, this doesn't apply to Flatpaks, since installing them can be automatically done in the background, and therefore isn't intrusive.
I've updated the updates logic diagram to reflect how Flatpak updates should be handled. Something along these lines seems like the way to go; review and feedback on the design would be good though.
One obvious thing to check is whether we want to have the same logic for Flatpaks and non-Flatpaks when automatic updates is turned off.