Remove deprecated Spree::Order#finalize!

Please, use Spree::Order#complete! now.

Ref solidusio#4260

core/app/models/spree/order.rb

@@ -395,18 +395,6 @@ def valid_credit_cards
  Spree::CreditCard.where(id: credit_card_ids)
  end
 
- # TODO: Remove on Solidus 4.0
- # @api private
- def finalize!
- Spree::Deprecation.warn <<~MSG
- Calling `Spree::Order#finalize!` is discouraged. Instead, use
- `Spree::Order#complete!`, which goes through all the needed safety
- checks before finalizing an order. This method will be removed
- altogether on Solidus 4.0.
- MSG
- finalize
- end
-
  def fulfill!
  shipments.each { |shipment| shipment.update_state if shipment.persisted? }
  updater.update_shipment_state

core/spec/models/spree/order/finalizing_spec.rb

@@ -124,16 +124,4 @@
  end
  end
  end
-
- context '#finalize!' do
- it 'deprecates method and goes ahead' do
- order = create(:order_ready_to_complete)
-
- expect(Spree::Deprecation).to receive(:warn).with(/discouraged/)
-
- order.finalize!
-
- expect(order.state).to eq("confirm")
- end
- end
 end