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

iOS_SDK/OneSignalSDK/OneSignalUser/Source/OSUserRequests.swift

@@ -643,6 +643,7 @@ class OSRequestCreateUser: OneSignalRequest, OSUserRequest {
         propertiesObject["timezone_id"] = propertiesModel.timezoneId
         params["properties"] = propertiesObject
 
+        params["refresh_device_metadata"] = true
         self.parameters = params
         self.updatePushSubscriptionModel(pushSubscriptionModel)
         self.method = POST