[improve][broker] Change partition metadata not-found log to warn (#26381)

Author: Technoboy-

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

@@ -1233,10 +1233,19 @@ protected void handlePartitionMetadataRequest(CommandPartitionedTopicMetadata pa
                                 topicExistsInfo.recycle();
                             }).exceptionally(ex -> {
                                 lookupSemaphore.release();
-                                log.error()
-                                        .attr("topic", topicName)
-                                        .exception(ex)
-                                        .log("Failed to get partition metadata");
+                                Throwable actEx = FutureUtil.unwrapCompletionException(ex);
+                                if (actEx instanceof WebApplicationException restException
+                                        && restException.getResponse().getStatus() == NOT_FOUND.getStatusCode()) {
+                                    log.warn()
+                                            .attr("topic", topicName)
+                                            .exceptionMessage(actEx)
+                                            .log("Failed to get partition metadata for nonexistent resource");
+                                } else {
+                                    log.error()
+                                            .attr("topic", topicName)
+                                            .exception(ex)
+                                            .log("Failed to get partition metadata");
+                                }
                                 writeAndFlush(
                                         Commands.newPartitionMetadataResponse(ServerError.MetadataError,
                                                 "Failed to get partition metadata",