Upstream installer's .desktop file is unhandled

[zelikos]

Something I didn't notice because I use GNOME and don't keep a Desktop folder on my system, but if the Desktop folder is present, the upstream Resolve installer creates a .desktop file there. Obviously, it doesn't point to the distrobox container, so it won't work, and could cause confusion. We should either delete it, or modify it as part of add-davinci-launcher like we do with the others