Fix nothing logged in frontend when log_level warn is set. https://github.com/Koenkk/zigbee2mqtt/issues/5812

lib/util/logger.js

@@ -133,6 +133,10 @@ function logOutput() {
     }
 }
 
+logger.addTransport = (transport) => {
+    transport.level = transportsToUse[0].level;
+    logger.add(transport);
+};
 logger.cleanup = cleanup;
 logger.logOutput = logOutput;
 logger.getLevel = () => winstonToZ2mLevel(transportsToUse[0].level);