check config backup as welcome page gate

Author: DedeHai

wled00/wled.cpp

@@ -474,7 +474,7 @@ void WLED::setup()
 
   if (needsCfgSave) serializeConfigToFS(); // usermods required new parameters; need to wait for strip to be initialised #4752
 
-  if (strcmp(multiWiFi[0].clientSSID, DEFAULT_CLIENT_SSID) == 0)
+  if (strcmp(multiWiFi[0].clientSSID, DEFAULT_CLIENT_SSID) == 0 && !configBackupExists())
     showWelcomePage = true;
   WiFi.persistent(false);
   WiFi.onEvent(WiFiEvent);