Fix crash when refusing order from the Order page

[Atala]

#4875

Refused order status is also valid when all tasks of a delivery are cancelled

[r0xsh]

Should allow transition from refused to cancelled into state_machine.yml

[alexsegura]

You could also just allow the transition from refused to cancelled in app/config/state_machine.yml

cancel:
  from: [new, accepted, started, ready, refused]
  to: cancelled