private boolean namespaceExists(PulsarClusterInfo pulsarClusterInfo, String tenant, String namespace)
            throws Exception {
        List<String> namespaces = PulsarUtils.getNamespaces(restTemplate, pulsarClusterInfo, tenant);
        return namespaces.contains(namespace);
    }
Check whether the Pulsar namespace exists under the specified tenant.

@param pulsarClusterInfo pulsar cluster info
@param tenant pulsar tenant info
@param namespace pulsar namespace info
@return true or false
@throws Exception any exception if occurred
inlong-manager/manager-service/src/main/java/org/apache/inlong/manager/service/resource/queue/pulsar/PulsarOperator.java