events: Fix can_subscribe_other_users not being set properly.

I don't understand why this didn't cause test failures in CI; this
change was clearly required and test_change_realm_property was failing
consistently for me locally.

zerver/lib/events.py

@@ -466,6 +466,7 @@ def apply_event(state: Dict[str, Any],
             if (field in ['realm_create_stream_by_admins_only',
                           'realm_waiting_period_threshold']) and 'can_create_streams' in state:
                 state['can_create_streams'] = user_profile.can_create_streams()
+                state['can_subscribe_other_users'] = user_profile.can_subscribe_other_users()
         elif event['op'] == "update_dict":
             for key, value in event['data'].items():
                 state['realm_' + key] = value