OrderService.getDiscontinuationOrder() should ignore voided orders

An order can have multiple previous orders to it although only one can be unvoided, i.e. one can void the original discontinuation order and place a new one as the work flow for 'updating' startDate, orderReason, orderReasonNonCode on a discontinuation order.

TODO:
1- OrderService.getDiscontinuationOrder() to ignore voided orders