adwaita-icon-theme is missing window action icons

[ Impact ]

Various window-* operation icons are missing in the adwaita-icon-theme (but available in the full one) even if they're fundamental for gtk apps.

In focal the icons are:

dpkg -L adwaita-icon-theme | grep "window-.*"
/usr/share/icons/Adwaita/scalable/ui/window-close-symbolic.svg
/usr/share/icons/Adwaita/scalable/ui/window-maximize-symbolic.svg
/usr/share/icons/Adwaita/scalable/ui/window-minimize-symbolic.svg
/usr/share/icons/Adwaita/scalable/ui/window-new-symbolic.svg
/usr/share/icons/Adwaita/scalable/ui/window-restore-symbolic.svg

[ Test case ]

dpkg -L adwaita-icon-theme | grep "window-.*"

It should contain

/usr/share/icons/Adwaita/16x16/legacy/window-close.png
/usr/share/icons/Adwaita/16x16/legacy/window-new.png
/usr/share/icons/Adwaita/16x16/ui/window-close-symbolic.symbolic.png
/usr/share/icons/Adwaita/16x16/ui/window-maximize-symbolic.symbolic.png
/usr/share/icons/Adwaita/16x16/ui/window-minimize-symbolic.symbolic.png
/usr/share/icons/Adwaita/16x16/ui/window-new-symbolic.symbolic.png
/usr/share/icons/Adwaita/16x16/ui/window-restore-symbolic.symbolic.png
/usr/share/icons/Adwaita/22x22/legacy/window-close.png
/usr/share/icons/Adwaita/22x22/legacy/window-new.png
/usr/share/icons/Adwaita/24x24/legacy/window-close.png
/usr/share/icons/Adwaita/24x24/legacy/window-new.png
/usr/share/icons/Adwaita/24x24/ui/window-close-symbolic.symbolic.png
/usr/share/icons/Adwaita/24x24/ui/window-maximize-symbolic.symbolic.png
/usr/share/icons/Adwaita/24x24/ui/window-minimize-symbolic.symbolic.png
/usr/share/icons/Adwaita/24x24/ui/window-new-symbolic.symbolic.png
/usr/share/icons/Adwaita/24x24/ui/window-restore-symbolic.symbolic.png
/usr/share/icons/Adwaita/32x32/legacy/window-close.png
/usr/share/icons/Adwaita/32x32/legacy/window-new.png
/usr/share/icons/Adwaita/32x32/ui/window-close-symbolic.symbolic.png
/usr/share/icons/Adwaita/32x32/ui/window-maximize-symbolic.symbolic.png
/usr/share/icons/Adwaita/32x32/ui/window-minimize-symbolic.symbolic.png
/usr/share/icons/Adwaita/32x32/ui/window-new-symbolic.symbolic.png
/usr/share/icons/Adwaita/32x32/ui/window-restore-symbolic.symbolic.png
/usr/share/icons/Adwaita/48x48/legacy/window-close.png
/usr/share/icons/Adwaita/48x48/legacy/window-new.png
/usr/share/icons/Adwaita/48x48/ui/window-close-symbolic.symbolic.png
/usr/share/icons/Adwaita/48x48/ui/window-maximize-symbolic.symbolic.png
/usr/share/icons/Adwaita/48x48/ui/window-minimize-symbolic.symbolic.png
/usr/share/icons/Adwaita/48x48/ui/window-new-symbolic.symbolic.png
/usr/share/icons/Adwaita/48x48/ui/window-restore-symbolic.symbolic.png
/usr/share/icons/Adwaita/64x64/ui/window-close-symbolic.symbolic.png
/usr/share/icons/Adwaita/64x64/ui/window-maximize-symbolic.symbolic.png
/usr/share/icons/Adwaita/64x64/ui/window-minimize-symbolic.symbolic.png
/usr/share/icons/Adwaita/64x64/ui/window-new-symbolic.symbolic.png
/usr/share/icons/Adwaita/64x64/ui/window-restore-symbolic.symbolic.png
/usr/share/icons/Adwaita/96x96/ui/window-close-symbolic.symbolic.png
/usr/share/icons/Adwaita/96x96/ui/window-maximize-symbolic.symbolic.png
/usr/share/icons/Adwaita/96x96/ui/window-minimize-symbolic.symbolic.png
/usr/share/icons/Adwaita/96x96/ui/window-new-symbolic.symbolic.png
/usr/share/icons/Adwaita/96x96/ui/window-restore-symbolic.symbolic.png
/usr/share/icons/Adwaita/scalable/ui/window-close-symbolic.svg
/usr/share/icons/Adwaita/scalable/ui/window-maximize-symbolic.svg
/usr/share/icons/Adwaita/scalable/ui/window-minimize-symbolic.svg
/usr/share/icons/Adwaita/scalable/ui/window-new-symbolic.svg
/usr/share/icons/Adwaita/scalable/ui/window-restore-symbolic.svg

[ Regression potential ]

Fixed-size icons may be chosen in some cases, leading some slight quality loss.