flake: Remove rycee's firefox addons repo

flake.lock

@@ -47,29 +47,6 @@
         "type": "github"
       }
     },
-    "firefox-addons": {
-      "inputs": {
-        "nixpkgs": [
-          "nixpkgs-unstable"
-        ]
-      },
-      "locked": {
-        "dir": "pkgs/firefox-addons",
-        "lastModified": 1753157005,
-        "narHash": "sha256-fTdJ2yYjR8O3kEWsveBGu/d8ilEFxVnGkF4wS3N1Was=",
-        "owner": "rycee",
-        "repo": "nur-expressions",
-        "rev": "a38f383959d8bf0c1d5d555469a4c63c4632701f",
-        "type": "gitlab"
-      },
-      "original": {
-        "dir": "pkgs/firefox-addons",
-        "owner": "rycee",
-        "ref": "master",
-        "repo": "nur-expressions",
-        "type": "gitlab"
-      }
-    },
     "flake-parts": {
       "inputs": {
         "nixpkgs-lib": "nixpkgs-lib"
@@ -336,7 +313,6 @@
       "inputs": {
         "agenix": "agenix",
         "colmena": "colmena",
-        "firefox-addons": "firefox-addons",
         "flake-parts": "flake-parts",
         "home-manager": "home-manager",
         "home-manager-unstable": "home-manager-unstable",