Hide menubar on newer QEMU versions

Newer QEMU versions since https://github.com/qemu/qemu/commit/dbccb1a5a1b5b14b78ea6b27bb562e8cd0a8f317 (7.2.0) can hide the menubar on GTK using -display gtk,show-menubar=off.

This makes the patches in https://gitlab.com/emulation-as-a-service/emulators/qemu-eaas/-/blob/90092abe0355507db0399be9e008c6f4f26e209b/gtk.patch or https://gitlab.com/emulation-as-a-service/emulators/qemu-eaas/-/blob/d98d9d5e8f0b9dadcbddaf13a59cf901b7160d2e/Dockerfile#L18 not necessary anymore.