flake.nix: Remove reference to patched nixpkgs for carbon, as the issue is patched upstream now

flake.lock

@@ -552,22 +552,6 @@
         "type": "github"
       }
     },
-    "nixpkgs-carbon": {
-      "locked": {
-        "lastModified": 1751206202,
-        "narHash": "sha256-VjK8pEv4cfDpCTh4KW1go98kP25j7KdTNEce342Bh/Y=",
-        "owner": "clerie",
-        "repo": "nixpkgs",
-        "rev": "ac4ac98609c1b30c378458ab7207a9a5b5148457",
-        "type": "github"
-      },
-      "original": {
-        "owner": "clerie",
-        "ref": "clerie/always-setup-netdevs",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "nixpkgs-regression": {
       "locked": {
         "lastModified": 1643052045,
@@ -768,7 +752,6 @@
         "nixos-hardware": "nixos-hardware",
         "nixpkgs": "nixpkgs_5",
         "nixpkgs-0dc1c7": "nixpkgs-0dc1c7",
-        "nixpkgs-carbon": "nixpkgs-carbon",
         "nurausstieg": "nurausstieg",
         "rainbowrss": "rainbowrss",
         "scan-to-gpg": "scan-to-gpg",