Various bugs found

Following on from #18503 and #18217

• Skip mod doesn't always increment the mod progress number

• Skip mod, if it's the last mod, it hangs on Installing Collection. It should probably be skippable, but then finish collection gracefully and leave it as incomplete. Maybe pause it? We need to work out the right UX here

• Collection pausing shows a notification that doesn't go away. This should be a toast

• When installing own collection, this happened