Add organisation info to branding requests

This will let us know which organisation the person asking for the
branding is from. This should reduce how often we have to go back to
them and ask.

app/utils.py

@@ -437,6 +437,8 @@ class AgreementInfo:
             self.domain_names,
         ), None)
 
+        self._domain = email_address_or_domain.split('@')[-1]
+
         (
             self.owner,
             self.crown_status,
@@ -469,7 +471,7 @@ class AgreementInfo:
                 }.get(self.crown_status),
             )
         else:
-            return 'Can’t tell'
+            return 'Can’t tell (domain is {})'.format(self._domain)
 
     @property
     def as_jinja_template(self):