lorri: make notifications service auto-start if enabled

Without this fix, the notifications service would need to start by hand
every time.

@moduon MT-1075

modules/services/lorri.nix

@@ -133,6 +133,10 @@ in
             in
             "PATH=${path}";
         };
+
+        Install = {
+          WantedBy = [ "lorri.service" ];
+        };
       };
     };
   };