nixos/fwupd: do no use renamed options in tests

nixos/tests/installed-tests/fwupd.nix

···
 
   testConfig = {
     services.fwupd.enable = true;
-    services.fwupd.disabledPlugins = lib.mkForce []; # don't disable test plugin
+    services.fwupd.daemonSettings.DisabledPlugins = lib.mkForce [ ]; # don't disable test plugin
     services.fwupd.enableTestRemote = true;
   };
 }