Comment 2 for bug 1761574

When I first implemented this I wasn't sure the best way to exclude "system" snaps as they don't provide any metadata to determine this. I think perhaps just excluding snaps without .desktop files is probably the best solution.

The reason those snaps have icons in GNOME Software is there's no icon embedded in the snap (or .desktop file with icon name) and in G-S we pull the icon from the store. This doesn't matter if we do the above.