Fetch missing stored products in Order Detail

[pmusolino]

While I was working on this task, I discovered that the implementation used for checking locally if the products are virtual or downloadable, is not the ideal solution since during the first launch of the app, we don't have the information related to the products (that are downloaded elsewhere, and stored locally), because we fetch them from Core Data. This means that all the references to products in OrderDetailsDataSource are not reliable.

The ideal solution would be to fetch all the missing stored products like Android already do.