Combine Clients wizard; Individuals now also match Sole Traders

The Combine Clients wizard now matches Sole Traders when an Individual is first selected.

In addition, the New Client wizard will also include Sole Traders in the list of suggested matches - when entering an Individual.

Note, Sole Traders are individuals that also are in business, so it makes sense to include Sole Traders.

In addition, the Business Layer function finBL.ClientTypes.GetSoleTraderPksList was not working properly, typically returning a blank list.