examples/deploy-krops: fix duplicate import error

`qemu-vm.nix` is already imported in `vm-config.nix` but under a
different path.
This causes an "already declared" error on NixOS 23.11.

examples/krops-vm-configuration.nix

@@ -3,6 +3,5 @@
     ./configuration.nix
     <nix-bitcoin/modules/deployment/krops.nix>
     <qemu-vm/vm-config.nix>
-    <nixpkgs/nixos/modules/virtualisation/qemu-vm.nix>
   ];
 }