Unleashed integration - add setting to prevent new customers being created in Unleashed for orders Synced from Mintsoft

Unleashed will create new customers for orders arriving from Mintsoft where it deems that customer does not already exist. This is a useful feature for ecommerce orders if you want separate customers per web order for example. However it can lead to unintended and undesired new customers being created in Unleashed with orders auto created and despatched against that customer before the issue is noticed and addressed. Currently if "Group By Channel on Export" is enabled, Unleashed checks the channel name and matches that to an Unleashed customer. However any change whatsoever to the channel name or customer name in unleashed will cause that matching to be broken and Unleashed will create a new customer and start syncing orders to it. Occasionally a Mintsoft updatewill cause a MS channel to UL customer link that previously was fine to be broken, resulting in a new customer being created in Unleashed. This results in a nightmare for accounts reconciliation down the line. This has already happened to us 7 or 8 times in 2 months.