esp_wifi_deinit: Return ESP_ERR_WIFI_NOT_STOPPED if wifi is not stopped

Add test case to test this workflow

components/esp_wifi/src/wifi_init.c

@@ -118,7 +118,7 @@ esp_err_t esp_wifi_deinit(void)
 
     if (esp_wifi_get_user_init_flag_internal()) {
         ESP_LOGE(TAG, "Wi-Fi not stop");
-        return ESP_FAIL; 
+        return ESP_ERR_WIFI_NOT_STOPPED;
     }
 
     esp_supplicant_deinit();