Backport !1055 “gs-app-list: Detect duplicates also by GsApp instance address” to gnome-41
There could happen that a GsApp instance had been added to the list multiple times, but it was not caught, due to refining an app, which is also in the list, but as a wildcard, which "hides" the other instance in the list.
Closes #1471 (closed)
Trivial backport of !1055 (merged) to gnome-41
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