Remove unnecessary spec helper module

These shared examples were used in only one spec file. It's much easier
to read having all the related specs in one file instead of hiding some
in a helper module.

It's also one less file to load whenever we run specs.

spec/base_spec_helper.rb

@@ -231,7 +231,6 @@ RSpec.configure do |config|
   config.include PreferencesHelper
   config.include OpenFoodNetwork::FiltersHelper
   config.include OpenFoodNetwork::EnterpriseGroupsHelper
-  config.include OpenFoodNetwork::ProductsHelper
   config.include OpenFoodNetwork::DistributionHelper
   config.include OpenFoodNetwork::HtmlHelper
   config.include ActionView::Helpers::DateHelper

spec/controllers/api/v0/products_controller_spec.rb

@@ -52,7 +52,20 @@ describe Api::V0::ProductsController, type: :controller do
       expect(response.status).to eq(404)
     end
 
-    include_examples "modifying product actions are restricted"
+    it "cannot create a new product if not an admin" do
+      api_post :create, product: { name: "Brand new product!" }
+      assert_unauthorized!
+    end
+
+    it "cannot update a product" do
+      api_put :update, id: product.to_param, product: { name: "I hacked your store!" }
+      assert_unauthorized!
+    end
+
+    it "cannot delete a product" do
+      api_delete :destroy, id: product.to_param
+      assert_unauthorized!
+    end
   end
 
   context "as an enterprise user" do

spec/support/products_helper.rb

@@ -1,22 +0,0 @@
-# frozen_string_literal: true
-
-module OpenFoodNetwork
-  module ProductsHelper
-    shared_examples "modifying product actions are restricted" do
-      it "cannot create a new product if not an admin" do
-        api_post :create, product: { name: "Brand new product!" }
-        assert_unauthorized!
-      end
-
-      it "cannot update a product" do
-        api_put :update, id: product.to_param, product: { name: "I hacked your store!" }
-        assert_unauthorized!
-      end
-
-      it "cannot delete a product" do
-        api_delete :destroy, id: product.to_param
-        assert_unauthorized!
-      end
-    end
-  end
-end