docs: remove old and dead BT video example link

docs/zh_CN/api-guides/esp-ble-mesh/ble-mesh-index.rst

@@ -230,7 +230,6 @@ ESP-BLE-MESH 示例
 ESP-BLE-MESH 演示视频
 ======================
 
-* `Provisioning of ESP-BLE-MESH nodes using Smartphone App <https://download.espressif.com/BLE_MESH/Docs4Customers/esp-ble-mesh-demo.mp4>`_
 * `Espressif Fast Provisioning using ESP-BLE-MESH App <https://dl.espressif.com/BLE/public/ESP32_BLE_Mesh_Fast_Provision.mp4>`_
 * `Espressif ESP-BLE-MESH and Wi-Fi Coexistence <https://dl.espressif.com/BLE/public/ESP_BLE_MESH_WIFI_Coexistence.mp4>`_