Prevent a purchase invoice being entered against a purchase order that in on 'Hold'

When a Purchase order has been placed on hold, it should not be possible to record an order invoice against the PO.

This would mean any PO's with GRN issues could be stopped from further accidental processing.

It would on mirror the 'On Hold' status is SOP, which when a sales or in on hold it does not print/ process an invoice for that order.