Enable nvidia nix-required-mounts

This allows running derivations which depend on cuda runtime without
breaking the sandbox. We only need to add `requiredSystemFeatures = [ "cuda" ];`
to the derivation.

m/module/nvidia.nix

@@ -1,7 +1,7 @@
 { lib, config, ... }:
 {
   # Configure Nvidia driver to use with CUDA
-  hardware.nvidia.package = config.boot.kernelPackages.nvidiaPackages.production;
+  hardware.nvidia.package = lib.mkDefault config.boot.kernelPackages.nvidiaPackages.production;
   hardware.nvidia.open = lib.mkDefault (builtins.abort "hardware.nvidia.open not set");
   hardware.graphics.enable = true;
   nixpkgs.config.nvidia.acceptLicense = true;