Improve order factories

[luisramos0]

What we should change and why (this is tech debt)

There's so much stuff happening on the order workflow that in specs we should never set order.state. The order.state should be achieved through the workflow order.next.

This task is to remove all uses of order state in spec tests, for example:
let!(:order1) { create(:order, state: 'complete', completed_at: 1.day.ago, distributor: dist1, billing_address: create(:address) ) }

Some specs where this is done:

• spec/controllers/admin/bulk_line_items_controller_spec.rb
• spec/controllers/api/orders_controller_spec.rb:
• spec/controllers/spree/api/line_items_controller_spec.rb
• spec/features/admin/adjustments_spec.rb
• spec/features/admin/bulk_order_management_spec.rb
• spec/lib/open_food_network/order_and_distributor_report_spec.rb
• spec/mailers/producer_mailer_spec.rb
• spec/serializers/order_serializer_spec.rb

Impact and timeline

Better and more correct specs.