nixos/galene: set proper SystemCallFilter

nixos/modules/services/web-apps/galene.nix

···
           RestrictRealtime = true;
           RestrictSUIDSGID = true;
           SystemCallArchitectures = "native";
-          SystemCallFilter = [ "@system-service" "~@privileged" "~@resources" ];
+          SystemCallFilter = [ "@system-service" "~@privileged" ];
           UMask = "0077";
         }
       ];