Launcher window is created with no WM class or name on Linux

When the Minecraft launcher opens, it doesn't have an X11 class or name, so any script that listens for new windows can't determine that it's a Minecraft window.

Presumably the name and class are set after the window is created, since xprop reports both name and class once the launcher is opened, but at a minimum the class should be set when the window is created, not afterwards.