Delete cancel moves when a production is draft
We've got a support request form a user that processed a production with cancelled moves and then realized that stock for productions did not get udpated.
This is because the production was cancelled and then moved back to draft.
As cancel is a final state on Stock move I think it makes sense to delete the canceled moves when going back to draft so the user will notice that there are no moves for the production and will fix it (manually or using the explode_bom button)