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
     )