Feature flag "rabbitmq_4.1.0" not documented

### Describe the bug The "rabbitmq_4.1.0" feature flag, is not documented in https://www.rabbitmq.com/docs/feature-flags#core-feature-flags but shown on RabbitMQ server in the Management UI under Admin > Feature Flags. ### Reproduction steps 1. Go to https://www.rabbitmq.com/docs/feature-flags#core-feature-flags ### Expected behavior Should show the feature flag in the documentation. ### Additional context _No response_