logind-dbus: refuse multiple jobs in method_do_shutdown_or_sleep too

Fixes #30917

src/login/logind-dbus.c

@@ -2128,6 +2128,12 @@ static int method_do_shutdown_or_sleep(
         if (r != 0)
                 return r;
 
+        if (m->delayed_action)
+                return sd_bus_error_setf(error, BUS_ERROR_OPERATION_IN_PROGRESS,
+                                         "Action %s already in progress, refusing requested %s operation.",
+                                         handle_action_to_string(m->delayed_action->handle),
+                                         handle_action_to_string(a->handle));
+
         /* reset case we're shorting a scheduled shutdown */
         m->unlink_nologin = false;
         reset_scheduled_shutdown(m);