Move unknown organisation logic into Jinja

Human readable content like this doesn’t really belong in the model
layer, it’s more natural to have it in the presentation layer.

app/models/organisation.py

@@ -101,21 +101,6 @@ class Organisation(JSONModel):
             self.request_to_go_live_notes = None
             self.email_branding_id = None
 
-    @property
-    def as_agreement_statement_for_go_live_request(self):
-        return '{} (organisation is {}, {}).'.format(
-            {
-                False: 'No',
-                None: 'Can’t tell',
-            }.get(self.agreement_signed),
-            self.name,
-            {
-                True: 'a crown body',
-                False: 'a non-crown body',
-                None: 'crown status unknown',
-            }.get(self.crown),
-        )
-
     def as_info_for_branding_request(self, fallback_domain):
         return self.name or 'Can’t tell (domain is {})'.format(fallback_domain)