Refactor to pass through whole postal address

It’s a bit cleaner to not be passing through multiple variables which
are properties of the same object.

app/main/views/uploads.py

@@ -299,8 +299,7 @@ def uploaded_letter_preview(service_id, file_id):
         message=error_message,
         error_code=error_shortcode,
         form=form,
-        recipient=postal_address.as_single_line,
-        international=postal_address.international,
+        postal_address=postal_address,
         re_upload_form=re_upload_form
     )
 

app/templates/views/uploads/preview.html

@@ -48,11 +48,11 @@
     {% if status == 'valid' %}
     <div class="js-stick-at-bottom-when-scrolling">
       <p class="top-gutter-0 bottom-gutter-1-2 send-recipient" title="{{ recipient }}">
-        Recipient: {{ recipient }}
+        Recipient: {{ postal_address.as_single_line }}
       </p>
 
       {% if current_service.live %}
-        {% if international %}
+        {% if postal_address.international %}
           <p class="govuk-body">
             Postage: international
           </p>