Fix testGetStatsIfPartitionNotExists

Author: BewareMyPower

pulsar-broker/src/test/java/org/apache/pulsar/broker/admin/AdminApi2Test.java

@@ -3746,6 +3746,7 @@ public void testGetStatsIfPartitionNotExists() throws Exception {
         final String partitionedTp = BrokerTestUtil.newUniqueName("persistent://" + defaultNamespace + "/tp");
         admin.topics().createPartitionedTopic(partitionedTp, 1);
         TopicName partition0 = TopicName.get(partitionedTp).getPartition(0);
+        admin.lookups().lookupTopic(partition0.toString()); // trigger loading namespace bundles
         boolean topicExists1 = pulsar.getBrokerService().getTopic(partition0.toString(), false).join().isPresent();
         assertTrue(topicExists1);
         // Verify topics-stats works.