Backport !1068 “gs-details-page: Reload the page only when the app is idle” to gnome-41

It doesn't look good when the user installs/removes an app from the details page and the page is reloading in the middle of the install/remove process. This can be seen for example with flatpaks, when the applications installs also its runtime. There are issued several reload requests, after each installed part of the app or the runtime (the runtime, the locale part, the app itself).

The reload can lost track of the install progress too, when it gets a different app instance during the reload.

Closes #1510 (closed)

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Trivial backport of !1068 (merged) to gnome-41.