Doc: [OCP] Clarify how to expose console

In the Broker on OCP doc (https://access.redhat.com/documentation/en-us/red_hat_amq/7.7/html-single/deploying_amq_broker_on_openshift/index#connecting-broker-to-management-console_broker-ocp), we discuss how to configure client connections to the management console. However, we don't mention that expose=true must be specified in the CR to trigger the Operator to automatically create a dedicated Service and Route on the broker Pod.