wallpaper: Mishandling of picture-uri
x-d-p-gnome's wallpaper code seems to mishandle the picture-uri setting (and picture-uri-dark) in two ways:
- It inserts a raw path into picture-uri, and not a URI. I assume this happens to work with mutter, but any other app expecting to read a URI from picture-uri won't fare too well with this.
- It always copies the wallpaper into ~/.config/background. This means that if the portal is used to set the wallpaper twice in a row, the second wallpaper change won't change the picture-uri setting. Therefore, an app monitoring picture-uri for changes will never be notified that the wallpaper changed.
This is a repost from an x-d-p-gtk issue that seems to effect x-d-p-gnome also