* When output-bindings config is explicitly used for StreamBridge and the RabbitMQ routing-key-expression is provided, Spring Cloud Stream is throwing an exception due to a proper function is not found in the catalog. Bypassing this step and letting the bootstrapping continues if output-bindings and RabbitMQ routing-key-expression combination is used. * Adding tests to verify Resolves https://github.com/spring-cloud/spring-cloud-stream/issues/2921