Refactor the endpoint for listing workflow instances to use a more robust enum parsing method and improve validation. Update models to accept string collections for statuses and sub-statuses, which enables validating and parsing these enums directly within the endpoint.
The FetchProducts.cs and Product.cs files have been removed as they are no longer needed. Additionally, changes in the OrderBatchProcessor.cs and FetchOrders.cs reflect updates to order fetching logic to accommodate these removals.
