Backport !1021 “packagekit: Update GsApp state and kind only when created the app instance” to gnome-41

The gs_plugin_packagekit_add_results() can reuse GsApp instances from the plugin cache, which can already have set property state and kind, but this was not checked for, which could cause runtime warnings about invalid state or kind change.

A reproducer is to open Repositories dialog, which lists available repositories and the applications being installed in each of them (added as 'related'). These installed applications can have set state 'updatable' or have refined their 'kind' already.

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Trivial backport of !1021 (merged) to gnome-41.