added setting for wifi power save off

src/wifiscan.cpp

@@ -71,6 +71,7 @@ void wifi_sniffer_init(void) {
   ESP_ERROR_CHECK(
       esp_wifi_set_storage(WIFI_STORAGE_RAM)); // we don't need NVRAM
   ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_NULL));
+  ESP_ERROR_CHECK(esp_wifi_set_ps(WIFI_PS_NONE)); // no modem power saving
   ESP_ERROR_CHECK(esp_wifi_start()); // channel switch throws error without
   ESP_ERROR_CHECK(esp_wifi_set_promiscuous_filter(&filter)); // set frame filter
   ESP_ERROR_CHECK(esp_wifi_set_promiscuous_rx_cb(&wifi_sniffer_packet_handler));