Prefer a concern that set a variable instead of a global helper

Therefor, for the right controllers, simply implements:

```
include WhiteLabel

before_action :hide_ofn_navigation, only: [:show, :edit]
```

This is mort robust, since we're working in a controller level, not parsing URLs...

app/controllers/checkout_controller.rb

@@ -5,6 +5,7 @@ require 'open_food_network/address_finder'
 class CheckoutController < ::BaseController
   include OrderStockCheck
   include OrderCompletion
+  include WhiteLabel
 
   layout 'darkswarm'
 
@@ -27,6 +28,8 @@ class CheckoutController < ::BaseController
   before_action :associate_user
   before_action :check_authorization
 
+  before_action :hide_ofn_navigation, only: :edit
+
   helper 'spree/orders'
 
   def edit; end

app/controllers/concerns/white_label.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module WhiteLabel
+  extend ActiveSupport::Concern
+  include EnterprisesHelper
+
+  def hide_ofn_navigation
+    # if the distributor has the hide_ofn_navigation preference set to true
+    # then we should hide the OFN navigation
+    @hide_ofn_navigation = distributor.preferred_hide_ofn_navigation
+  end
+
+  private
+
+  def distributor
+    return current_distributor unless request.path.start_with?("/orders/")
+
+    # if we are on an order confirmation page,
+    # we need to get the distributor from the order, not the current one
+    Spree::Order.find_by(number: params[:id]).distributor
+  end
+end

app/controllers/enterprises_controller.rb

@@ -7,6 +7,7 @@ class EnterprisesController < BaseController
   helper Spree::ProductsHelper
   include OrderCyclesHelper
   include SerializerHelper
+  include WhiteLabel
 
   protect_from_forgery except: :check_permalink
 
@@ -14,6 +15,7 @@ class EnterprisesController < BaseController
   prepend_before_action :set_order_cycles, :require_distributor_chosen, :reset_order, only: :shop
 
   before_action :clean_permalink, only: :check_permalink
+  before_action :hide_ofn_navigation, only: :shop
 
   respond_to :js, only: :permalink_checker
 

app/controllers/split_checkout_controller.rb

@@ -10,6 +10,7 @@ class SplitCheckoutController < ::BaseController
   include CheckoutCallbacks
   include OrderCompletion
   include CablecarResponses
+  include WhiteLabel
 
   helper 'terms_and_conditions'
   helper 'checkout'
@@ -18,6 +19,7 @@ class SplitCheckoutController < ::BaseController
   helper OrderHelper
 
   before_action :set_checkout_redirect
+  before_action :hide_ofn_navigation, only: [:edit, :update]
 
   def edit
     redirect_to_step_based_on_order unless params[:step]

app/controllers/spree/orders_controller.rb

@@ -5,6 +5,7 @@ module Spree
     include OrderCyclesHelper
     include Rails.application.routes.url_helpers
     include CablecarResponses
+    include WhiteLabel
 
     layout 'darkswarm'
 
@@ -22,6 +23,7 @@ module Spree
     prepend_before_action :require_distributor_chosen, only: :edit
     before_action :check_hub_ready_for_checkout, only: :edit
     before_action :check_at_least_one_line_item, only: :update
+    before_action :hide_ofn_navigation, only: [:show, :edit]
 
     def show
       @order = Spree::Order.find_by!(number: params[:id])

app/helpers/enterprises_helper.rb

@@ -87,26 +87,4 @@ module EnterprisesHelper
       main_app.producers_url
     end
   end
-
-  def hide_ofn_navigation?
-    # if we are not on a shopfront, a cart page, checkout page or the order confirmation page
-    # then we should show the OFN navigation
-    # whatever the current distributor has set for the hide_ofn_navigation preference
-    return false unless current_distributor && current_page?(main_app.enterprise_shop_path(current_distributor)) || # shopfront
-                        request.path.start_with?(main_app.checkout_path) || # checkout
-                        current_page?(main_app.cart_path) || # cart
-                        request.path.start_with?("/orders/") # order confirmation
-
-    distributor = if request.path.start_with?("/orders/")
-                    # if we are on an order confirmation page,
-                    # we need to get the distributor from the order, not the current one
-                    Spree::Order.find_by(number: params[:id]).distributor
-                  else
-                    current_distributor
-                  end
-
-    # if the current distributor has the hide_ofn_navigation preference set to true
-    # then we should hide the OFN navigation
-    distributor.preferred_hide_ofn_navigation
-  end
 end

app/views/shared/menu/_large_menu.html.haml

@@ -10,7 +10,7 @@
           = t 'powered_by'
           %a{href: '/'}
             = t 'title'
-    - unless hide_ofn_navigation?
+    - unless @hide_ofn_navigation
       %ul.nav-main-menu
         - [*1..7].each do |menu_number|
           - menu_name = "menu_#{menu_number}"

spec/controllers/spree/orders_controller_spec.rb

@@ -91,6 +91,7 @@ describe Spree::OrdersController, type: :controller do
 
     it "redirects to shop when order is empty" do
       allow(controller).to receive(:current_distributor).and_return(distributor)
+      allow(distributor).to receive(:preferred_hide_ofn_navigation).and_return false
       allow(controller).to receive(:current_order_cycle).and_return(order_cycle)
       allow(controller).to receive(:current_order).and_return order
       allow(order).to receive_message_chain(:line_items, :empty?).and_return true