misc: Replace custom widgets with new libadwaita 1.6 widgets

Kévin Commaillerequested to merge
kcommaille/libadwaita-1.6 into main

We replace our custom Spinner widget with AdwSpinner, and we rename ButtonRow to LoadingButtonRow and replace it with AdwButtonRow where loading is not necessary.

Closes Move button rows to AdwButtonRow (#1434 - closed).

Edited by Kévin Commaille

Merge request reports