Init Order is not applied when `order_by` contains a value that is not orderable

[pehbehbeh]

The apply_criteria function expects a field_name to be present in the order criteria, but we do not set the value in the case order_by contains a value that is not orderable.

See https://github.com/naymspace/backpex/blob/0.3.1/lib/backpex/live_resource.ex#L1336