Bug#1021034: Gtk{Grid, List}View scrolling fix backport into Debian's 4.8 branch

[Алексей Шилин]

Hi,

I've backported all relevant upstream patches fixing this issue into my
Debian gtk4 bookworm/sid package branch [1]. *Maybe* it can be used as
a base for an official backport, but the diff is unfortunately not
particularly small, so it's up to gtk4 maintainers and the Release
Team. Anyway, testing is welcome.

This bug affects all GTK4 applications using GtkListView and/or
GtkGridView when there are enough items inside. The most prominent one
is nautilus, but there are others, too, like gnome-font-viewer. For
nautilus, it makes scrolling from bottom to top (and also from top to
almost-bottom as it just jumps to the end of the grid) impossible for
any directory with large enough items count, like /usr/share/doc or
/usr/bin.

 [1]
https://salsa.debian.org/AleksejShilin-guest/gtk4/-/tree/fixes/1021034-gtklistview-scrolling