fix(user/malte): darkman startup

Startup failed because the activation script that
updates the hyprpaper configuration was hitting
the hyprpaper backend before it was ready.

users/malte/default.nix

@@ -1,6 +1,7 @@
 {
   pkgs,
   lib,
+  config,
   nixosConfig,
   ...
 }: let
@@ -211,6 +212,12 @@ in {
         lng = 12.36;
       };
     };
+    # This ensures that the hyprpaper scripts for darkman only run after the
+    # backend for hyprpaper is running
+    systemd.user.services.darkman.Unit.After =
+      if builtins.hasAttr "hyprpaper" config.systemd.user.services
+      then ["hyprpaper.service"]
+      else [];
 
     services.mpris-proxy.enable = true;
     services.pasystray.enable = true;