Show {nav Detailed Tree View} by default in `KDirOperator`. This primarily affects the file open/save dialogs, because other clients generally set their preferred view mode manually.
This change will result in Open & Save dialogs displaying {nav Detailed Tree View} by default instead of {nav Simple View} (which is being transformed into a primarily visual browsing mode; see {T8552}). {nav Detailed Tree View} is better for content that is best located by its filename or metadata, which I would wager is more common, so it should be the default view. Also, bandwagon argument: Windows and GNOME both display the same view by default in their Open/Save dialogs now (macOS displays the navigation-friendly {Column View} by default, which sadly lacks a KDE equivalent).