add refresh_device_metadata to create user request

When the server receives a create user request, it doesn't automatically update IP and country for this user because this request can come from the SDK or from the customer's server.
By passing in a `refresh_device_metadata = true` property to the request body, we can let the server know to update IP and country based on where the request originated from.

Author: nan-li

OneSignalSDK/onesignal/core/src/main/java/com/onesignal/user/internal/backend/impl/UserBackendService.kt

@@ -34,6 +34,8 @@ internal class UserBackendService(
             requestJSON.put("properties", JSONObject().putMap(properties))
         }
 
+        requestJSON.put("refresh_device_metadata", true)
+
         val response = _httpClient.post("apps/$appId/users", requestJSON)
 
         if (!response.isSuccess) {