do not import selfprivacy overlay path, but use flake overlay output

flake.lock

@@ -32,11 +32,11 @@
       "inputs": {
         "hardware-configuration-nix": "hardware-configuration-nix",
         "nixpkgs": "nixpkgs",
-        "selfprivacy-overlay-path": "selfprivacy-overlay-path",
+        "selfprivacy-overlay": "selfprivacy-overlay",
         "userdata-json": "userdata-json"
       }
     },
-    "selfprivacy-overlay-path": {
+    "selfprivacy-overlay": {
       "locked": {
         "lastModified": 1689554432,
         "narHash": "sha256-hegMIgxBHUuRFbCecQpbjFfTHpduV3VZWr8OINtQO6k=",

flake.nix

@@ -4,7 +4,7 @@
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs";
 
-    selfprivacy-overlay-path.url =
+    selfprivacy-overlay.url =
       "git+https://git.selfprivacy.org/SelfPrivacy/selfprivacy-nix-repo.git";
 
     # these inputs are expected to be set by the caller
@@ -16,13 +16,12 @@
   outputs =
     { self
     , nixpkgs
-    , selfprivacy-overlay-path
+    , selfprivacy-overlay
     , userdata-json
     , hardware-configuration-nix
     }:
     let
       system = "x86_64-linux";
-      selfprivacy-overlay = import selfprivacy-overlay-path;
       userdata = builtins.fromJSON (builtins.readFile userdata-json);
       hardware-configuration = import hardware-configuration-nix;
     in
@@ -31,7 +30,7 @@
         just-nixos = nixpkgs.lib.nixosSystem {
           specialArgs = { inherit system userdata; };
           modules = [
-            { nixpkgs.overlays = [ selfprivacy-overlay ]; }
+            { nixpkgs.overlays = [ selfprivacy-overlay.overlay ]; }
             hardware-configuration
             ./configuration.nix
           ];