Always send account_email to WorldPay

https://eaflood.atlassian.net/browse/WC-536

This PR essentially reverts the change made in #278 - when AD users were locked out of their account, we wanted to avoid using an email address they may no longer have access to. However, our registration transfer feature solves that problem, so we can now be consistent about what address we use again.

app/services/waste_carriers_engine/worldpay_xml_service.rb

@@ -62,7 +62,7 @@ def build_payment_methods(xml)
     end
 
     def build_shopper(xml)
-      email = get_email
+      email = @transient_registration.account_email
 
       xml.shopper do
         xml.shopperEmailAddress email
@@ -100,13 +100,5 @@ def get_country_code(country)
       return "GB" if country.nil?
       country.alpha2
     end
-
-    def get_email
-      if @current_user.email == @transient_registration.account_email
-        @transient_registration.account_email
-      else
-        @transient_registration.contact_email
-      end
-    end
   end
 end

spec/services/waste_carriers_engine/worldpay_xml_service_spec.rb

@@ -26,27 +26,10 @@ module WasteCarriersEngine
       allow_any_instance_of(Order).to receive(:total_amount).and_return(10_000)
     end
 
-    describe "build_xml" do
-      context "when it's a digital registration" do
-        before do
-          current_user.email = transient_registration.account_email
-        end
-
-        it "returns correctly-formatted XML" do
-          xml = File.read("./spec/fixtures/files/request_to_worldpay.xml")
-          expect(worldpay_xml_service.build_xml).to eq(xml)
-        end
-      end
-
-      context "when it's an assisted digital registration" do
-        before do
-          current_user.email = "not-the-same-account@example.com"
-        end
-
-        it "returns correctly-formatted XML" do
-          xml = File.read("./spec/fixtures/files/request_to_worldpay_ad.xml")
-          expect(worldpay_xml_service.build_xml).to eq(xml)
-        end
+    describe "#build_xml" do
+      it "returns correctly-formatted XML" do
+        xml = File.read("./spec/fixtures/files/request_to_worldpay.xml")
+        expect(worldpay_xml_service.build_xml).to eq(xml)
       end
     end
   end