[Broker] Refine topic level backlog quota policies warning log (#11863)

### Motivation

Currently, if the `TopicPolicies` isn't initialized completely, the topic gets backlog quota will print the error log stack, this is not necessary, because after the TopicPolicies initialized, the topic level backlog quota will come into effect.

```
15:24:01.962 [bookkeeper-ml-workers-OrderedExecutor-2-0] WARN  org.apache.pulsar.broker.service.BacklogQuotaManager - Failed to read topic policies data, will apply the namespace backlog quota: topicName=persistent://public/ns3/t1
org.apache.pulsar.broker.service.BrokerServiceException$TopicPoliciesCacheNotInitException: Topic policies cache have not init.
	at org.apache.pulsar.broker.service.SystemTopicBasedTopicPoliciesService.getTopicPolicies(SystemTopicBasedTopicPoliciesService.java:148) ~[org.apache.pulsar-pulsar-broker-2.7.3.jar:2.7.3]
	at org.apache.pulsar.broker.service.BacklogQuotaManager.getBacklogQuota(BacklogQuotaManager.java:85) [org.apache.pulsar-pulsar-broker-2.7.3.jar:2.7.3]
	at org.apache.pulsar.broker.service.persistent.PersistentTopic.getBacklogQuota(PersistentTopic.java:2172) [org.apache.pulsar-pulsar-broker-2.7.3.jar:2.7.3]
	at org.apache.pulsar.broker.service.persistent.PersistentTopic.isBacklogQuotaExceeded(PersistentTopic.java:2181) [org.apache.pulsar-pulsar-broker-2.7.3.jar:2.7.3]
	at org.apache.pulsar.broker.service.ServerCnx.lambda$handleProducer$20(ServerCnx.java:1100) [org.apache.pulsar-pulsar-broker-2.7.3.jar:2.7.3]
	at java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:714) [?:?]
	at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506) [?:?]
	at java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073) [?:?]
	at org.apache.pulsar.broker.service.BrokerService$3.lambda$openLedgerComplete$2(BrokerService.java:1125) [org.apache.pulsar-pulsar-broker-2.7.3.jar:2.7.3]
	at java.util.concurrent.CompletableFuture.uniRunNow(CompletableFuture.java:815) [?:?]
	at java.util.concurrent.CompletableFuture.uniRunStage(CompletableFuture.java:799) [?:?]
	at java.util.concurrent.CompletableFuture.thenRun(CompletableFuture.java:2121) [?:?]
	at org.apache.pulsar.broker.service.BrokerService$3.openLedgerComplete(BrokerService.java:1111) [org.apache.pulsar-pulsar-broker-2.7.3.jar:2.7.3]
	at org.apache.bookkeeper.mledger.impl.ManagedLedgerFactoryImpl.lambda$asyncOpen$8(ManagedLedgerFactoryImpl.java:425) [org.apache.pulsar-managed-ledger-2.7.3.jar:2.7.3]
	at java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:714) [?:?]
	at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506) [?:?]
	at java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073) [?:?]
	at org.apache.bookkeeper.mledger.impl.ManagedLedgerFactoryImpl$2.initializeComplete(ManagedLedgerFactoryImpl.java:397) [org.apache.pulsar-managed-ledger-2.7.3.jar:2.7.3]
	at org.apache.bookkeeper.mledger.impl.ManagedLedgerImpl$3.operationComplete(ManagedLedgerImpl.java:476) [org.apache.pulsar-managed-ledger-2.7.3.jar:2.7.3]
	at org.apache.bookkeeper.mledger.impl.ManagedLedgerImpl$3.operationComplete(ManagedLedgerImpl.java:466) [org.apache.pulsar-managed-ledger-2.7.3.jar:2.7.3]
	at org.apache.bookkeeper.mledger.impl.MetaStoreImpl.lambda$getCursors$8(MetaStoreImpl.java:122) [org.apache.pulsar-managed-ledger-2.7.3.jar:2.7.3]
	at java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:714) [?:?]
	at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:478) [?:?]
	at org.apache.bookkeeper.common.util.OrderedExecutor$TimedRunnable.run(OrderedExecutor.java:203) [org.apache.bookkeeper-bookkeeper-common-4.12.0.jar:4.12.0]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [io.netty-netty-common-4.1.60.Final.jar:4.1.60.Final]
	at java.lang.Thread.run(Thread.java:834) [?:?]
```

### Modifications

Remove the error log stack.

pulsar-broker/src/main/java/org/apache/pulsar/broker/service/BacklogQuotaManager.java

@@ -91,9 +91,12 @@ public BacklogQuotaImpl getBacklogQuota(TopicName topicName, BacklogQuotaType ba
                     .map(TopicPolicies::getBackLogQuotaMap)
                     .map(map -> map.get(backlogQuotaType.name()))
                     .orElseGet(() -> getBacklogQuota(topicName.getNamespace(), policyPath, backlogQuotaType));
+        } catch (BrokerServiceException.TopicPoliciesCacheNotInitException e) {
+            log.debug("Topic policies cache have not init, will apply the namespace backlog quota: topicName={}",
+                    topicName);
         } catch (Exception e) {
-            log.warn("Failed to read topic policies data, will apply the namespace backlog quota: topicName={}",
-                    topicName, e);
+            log.error("Failed to read topic policies data, "
+                            + "will apply the namespace backlog quota: topicName={}", topicName, e);
         }
         return getBacklogQuota(topicName.getNamespace(), policyPath, backlogQuotaType);
     }