[fix][broker] Fix message drop record in producer stat (#22458)

Co-authored-by: ceceezhang <ceceezhang@tencent.com>
(cherry picked from commit cea1a9b)

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

@@ -749,7 +749,7 @@ public void updateRates() {
         }
         if (this.isNonPersistentTopic) {
             msgDrop.calculateRate();
-            ((NonPersistentPublisherStatsImpl) stats).msgDropRate = msgDrop.getRate();
+            ((NonPersistentPublisherStatsImpl) stats).msgDropRate = msgDrop.getValueRate();
         }
     }