Don't compile customers report data before search

Distributors, suppliers and order cycles are still loaded for the search
form.

app/controllers/spree/admin/reports_controller_decorator.rb

@@ -63,7 +63,7 @@ Spree::Admin::ReportsController.class_eval do
   def customers
     @report_types = report_types[:customers]
     @report_type = params[:report_type]
-    @report = OpenFoodNetwork::CustomersReport.new spree_current_user, params
+    @report = OpenFoodNetwork::CustomersReport.new spree_current_user, params, render_content?
     render_report(@report.header, @report.table, params[:csv], "customers_#{timestamp}.csv")
   end
 

lib/open_food_network/customers_report.rb

@@ -1,9 +1,10 @@
 module OpenFoodNetwork
   class CustomersReport
     attr_reader :params
-    def initialize(user, params = {})
+    def initialize(user, params = {}, compile_table = false)
       @params = params
       @user = user
+      @compile_table = compile_table
     end
 
     def header
@@ -25,6 +26,7 @@ module OpenFoodNetwork
     end
 
     def table
+      return [] unless @compile_table
       orders.map do |order|
         if is_mailing_list?
           [order.email,

spec/controllers/spree/admin/reports_controller_spec.rb

@@ -261,7 +261,7 @@ describe Spree::Admin::ReportsController, type: :controller do
 
     it "creates a CustomersReport" do
       expect(OpenFoodNetwork::CustomersReport).to receive(:new)
-        .with(@admin_user, {"test" => "foo", "controller" => "spree/admin/reports", "action" => "customers"})
+        .with(@admin_user, {"test" => "foo", "controller" => "spree/admin/reports", "action" => "customers"}, false)
         .and_return(report = double(:report))
       allow(report).to receive(:header).and_return []
       allow(report).to receive(:table).and_return []

spec/lib/open_food_network/customers_report_spec.rb

@@ -8,7 +8,7 @@ module OpenFoodNetwork
         user.spree_roles << Spree::Role.find_or_create_by_name!("admin")
         user
       end
-      subject { CustomersReport.new user }
+      subject { CustomersReport.new user, {}, true }
 
       describe "mailing list report" do
         before do
@@ -81,7 +81,7 @@ module OpenFoodNetwork
         user
       end
 
-      subject { CustomersReport.new user }
+      subject { CustomersReport.new user, {}, true }
 
       describe "fetching orders" do
         let(:supplier) { create(:supplier_enterprise) }