fix mDNS on network reconnect

src/web/WebStatusService.cpp

@@ -165,6 +165,7 @@ void WebStatusService::webStatusService(AsyncWebServerRequest * request) {
 // start the multicast UDP service so EMS-ESP is discoverable via .local
 void WebStatusService::mDNS_start() const {
 #ifndef EMSESP_STANDALONE
+    MDNS.end();
     if (!MDNS.begin(EMSESP::system_.hostname().c_str())) {
         EMSESP::logger().warning(F("Failed to start mDNS responder service"));
         return;