[SYS] Remove handleJsonQueue wrapper and use std::string (#2038)

Co-authored-by: Florian <1technophile@users.noreply.github.com>

main/ZgatewayIR.ino

@@ -148,7 +148,7 @@ void IRtoMQTT() {
     } else if (!isAduplicateSignal(MQTTvalue) && MQTTvalue != 0) { // conditions to avoid duplications of IR -->MQTT
       Log.trace(F("Adv data IRtoMQTT" CR));
       IRdata["origin"] = subjectIRtoMQTT;
-      handleJsonEnqueue(IRdata);
+      enqueueJsonObject(IRdata);
       Log.trace(F("Store val: %D" CR), MQTTvalue);
       storeSignalValue(MQTTvalue);
       if (repeatIRwMQTT) {