message: Fix warning in WiFiManager::debugPlatformInfo for ESP32
  This fixes an unused variable warning as the call to
  heap_caps_get_free_size() is not required.
  Tests:
  - Enable debug mode and verify free heap and ESP SDK
  version are correctly displayed
  - Cross check with the free heap reported via the captive
  portal info page
diff: @@ -2632,7 +2632,6 @@ void WiFiManager::debugPlatformInfo(){
  DEBUG_WM(F("system_get_boot_version():"),system_get_boot_version());
  DEBUG_WM(F("getFreeHeap(): "),(String)ESP.getFreeHeap());
  #elif defined(ESP32)
  - size_t freeHeap = heap_caps_get_free_size(MALLOC_CAP_8BIT);
  DEBUG_WM("Free heap: ", ESP.getFreeHeap());
  DEBUG_WM("ESP SDK version: ", ESP.getSdkVersion());
  // esp_chip_info_t chipInfo;
  