Hearing date field showing invalid format error when empty
Hearing date field showing invalid format error when empty

The django multiwidget we were using was returning data [None, None, None]
when all fields were empty, this was triggering the wrong validation
message. Now if all field values are empty value_from_datadict returns
an empty string.

[APDEV132]

ministryofjustice/manchester_traffic_offences_pleas,ministryofjustice/manchester_traffic_offences_pleas,ministryofjustice/manchester_traffic_offences_pleas,ministryofjustice/manchester_traffic_offences_pleas