fix esp32 erase w persistent

WiFiManager.cpp

@@ -2352,8 +2352,12 @@ bool WiFiManager::WiFi_eraseConfig() {
         return true;
       #endif
     #elif defined(ESP32)
+      bool ret;
       WiFi.mode(WIFI_AP_STA); // cannot erase if not in STA mode !
-      return WiFi.disconnect(true);
+      WiFi.persistent(true);
+      ret = WiFi.disconnect(true);
+      WiFi.persistent(false);
+      return ret;
     #endif
 }
 

WiFiManager.h

@@ -311,6 +311,7 @@ class WiFiManager
     boolean       _disableIpFields        = false; // edge case, if true, showxFields(false) forces ip fields off instead of default show when set
 
     // wrapper functions for handling setting and unsetting persistent for now.
+    bool          esp32persistent         = false;
     bool          _hasBegun               = false;
     void          _begin();
     void          _end();