[improve][broker] Do not print error logs for NotFound or Conflict errors when using the Admin API (apache#23928)

### Motivation

Currently, when there is a 404 or 409 error in the Admin API call, the broker prints the error logs.

```
ERROR org.apache.pulsar.broker.admin.v2.PersistentTopics - [xxx] Failed to get partitioned metadata topic persistent://xxx: Namespace not found
```

```
ERROR org.apache.pulsar.broker.admin.v2.Namespaces - Failed to get policies for namespace xxx: Namespace does not exist
```

```
ERROR org.apache.pulsar.broker.admin.v2.PersistentTopics - [xxx] Failed to create non-partitioned topic persistent:/xxx: This topic already exists
```

```
 [pulsar-web-44-1] ERROR org.apache.pulsar.broker.admin.AdminResource - [admin] Failed to create partitioned topic persistent://xxx

java.util.concurrent.CompletionException: org.apache.pulsar.broker.web.RestException: This topic already exists
```

These errors are related to the client side. The client can handle the error, so we don't need to print it in the broker log.

### Modifications

- Print a warning log for NotFound or Conflict errors in the Admin API.

Author: RobertIndie

pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/AdminResource.java

@@ -624,7 +624,12 @@ && pulsar().getConfig().isCreateTopicToRemoteClusterForReplication()) {
                     asyncResponse.resume(Response.noContent().build());
                 })
                 .exceptionally(ex -> {
-                    log.error("[{}] Failed to create partitioned topic {}", clientAppId(), topicName, ex);
+                    if (AdminResource.isConflictException(ex)) {
+                        log.info("[{}] Failed to create partitioned topic {}: {}", clientAppId(), topicName,
+                                ex.getMessage());
+                    } else {
+                        log.error("[{}] Failed to create partitioned topic {}", clientAppId(), topicName, ex);
+                    }
                     resumeAsyncResponseExceptionally(asyncResponse, ex);
                     return null;
                 });
@@ -885,13 +890,24 @@ protected static boolean isRedirectException(Throwable ex) {
                 == Status.TEMPORARY_REDIRECT.getStatusCode();
     }
 
+    protected static boolean isNotFoundOrConflictException(Throwable ex) {
+        return isNotFoundException(ex) || isConflictException(ex);
+    }
+
     protected static boolean isNotFoundException(Throwable ex) {
         Throwable realCause = FutureUtil.unwrapCompletionException(ex);
         return realCause instanceof WebApplicationException
                 && ((WebApplicationException) realCause).getResponse().getStatus()
                 == Status.NOT_FOUND.getStatusCode();
     }
 
+    protected static boolean isConflictException(Throwable ex) {
+        Throwable realCause = FutureUtil.unwrapCompletionException(ex);
+        return realCause instanceof WebApplicationException
+                && ((WebApplicationException) realCause).getResponse().getStatus()
+                == Status.CONFLICT.getStatusCode();
+    }
+
     protected static boolean isNot307And404Exception(Throwable ex) {
         return !isRedirectException(ex) && !isNotFoundException(ex);
     }

pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/v2/Namespaces.java

@@ -47,6 +47,7 @@
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.StreamingOutput;
+import org.apache.pulsar.broker.admin.AdminResource;
 import org.apache.pulsar.broker.admin.impl.NamespacesBase;
 import org.apache.pulsar.broker.admin.impl.OffloaderObjectsScannerUtils;
 import org.apache.pulsar.broker.web.RestException;
@@ -154,7 +155,11 @@ public void getPolicies(@Suspended AsyncResponse response,
                 .thenCompose(__ -> getNamespacePoliciesAsync(namespaceName))
                 .thenAccept(response::resume)
                 .exceptionally(ex -> {
-                    log.error("Failed to get policies for namespace {}", namespaceName, ex);
+                    if (AdminResource.isNotFoundOrConflictException(ex)) {
+                        log.info("Failed to get policies for namespace {}: {}", namespaceName, ex.getMessage());
+                    } else {
+                        log.error("Failed to get policies for namespace {}", namespaceName, ex);
+                    }
                     resumeAsyncResponseExceptionally(response, ex);
                     return null;
                 });

pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/v2/PersistentTopics.java

@@ -346,7 +346,7 @@ public void createNonPartitionedTopic(
         internalCreateNonPartitionedTopicAsync(authoritative, properties)
                 .thenAccept(__ -> asyncResponse.resume(Response.noContent().build()))
                 .exceptionally(ex -> {
-                    if (isNot307And404Exception(ex)) {
+                    if (isNot307And404Exception(ex) && !isConflictException(ex)) {
                         log.error("[{}] Failed to create non-partitioned topic {}", clientAppId(), topicName, ex);
                     }
                     resumeAsyncResponseExceptionally(asyncResponse, ex);
@@ -946,7 +946,7 @@ public void getPartitionedMetadata(
                     Throwable t = FutureUtil.unwrapCompletionException(ex);
                     if (!isRedirectException(t)) {
                         if (AdminResource.isNotFoundException(t)) {
-                            log.error("[{}] Failed to get partitioned metadata topic {}: {}",
+                            log.info("[{}] Failed to get partitioned metadata topic {}: {}",
                                     clientAppId(), topicName, ex.getMessage());
                         } else {
                             log.error("[{}] Failed to get partitioned metadata topic {}",