MINOR: Remove unnecessary check in ReplicaManager (#20588)

`setTopics` is executed at before, so the check is unnecessary.

Reviewers: Ken Huang <[email protected]>, Chia-Ping Tsai
 <[email protected]>

Author: DL1231

core/src/main/scala/kafka/server/ReplicaManager.scala

@@ -1261,11 +1261,11 @@ class ReplicaManager(val config: KafkaConfig,
         }
 
         val describeLogDirsResult = new DescribeLogDirsResponseData.DescribeLogDirsResult()
-          .setLogDir(absolutePath).setTopics(topicInfos)
+          .setLogDir(absolutePath)
+          .setTopics(topicInfos)
           .setErrorCode(Errors.NONE.code)
-          .setTotalBytes(totalBytes).setUsableBytes(usableBytes)
-        if (!topicInfos.isEmpty)
-          describeLogDirsResult.setTopics(topicInfos)
+          .setTotalBytes(totalBytes)
+          .setUsableBytes(usableBytes)
         describeLogDirsResult
 
       } catch {