Stop passing SMS sender when updating permissions

This is a redundant argument which no longer seems to be used by
anything.

app/models/service.py

@@ -53,30 +53,22 @@ class Service():
     def update_with_properties(self, properties):
         return service_api_client.update_service_with_properties(self.id, properties)
 
-    def switch_permission(self, permission, sms_sender=None):
+    def switch_permission(self, permission):
         return self.force_permission(
             permission,
             on=not self.has_permission(permission),
-            sms_sender=sms_sender
         )
 
-    def force_permission(self, permission, on=False, sms_sender=None):
+    def force_permission(self, permission, on=False):
 
         permissions, permission = set(self.permissions), {permission}
 
         return self.update_permissions(
             permissions | permission if on else permissions - permission,
-            sms_sender=sms_sender
         )
 
-    def update_permissions(self, permissions, sms_sender=None):
+    def update_permissions(self, permissions):
-
+        return self.update_with_properties({'permissions': list(permissions)})
-        data = {'permissions': list(permissions)}
-
-        if sms_sender:
-            data['sms_sender'] = sms_sender
-
-        self.update_with_properties(data)
 
     def toggle_research_mode(self):
         self.update_with_properties({