[Broker] Call .release() when discarding entry to prevent direct memory leak (apache#11748)

(cherry picked from commit 7906bb5)

Author: lhotari

pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentDispatcherSingleActiveConsumer.java

@@ -175,7 +175,9 @@ public synchronized void internalReadEntriesComplete(final List<Entry> entries,
                 Entry entry = iterator.next();
                 byte[] key = peekStickyKey(entry.getDataBuffer());
                 Consumer consumer = stickyKeyConsumerSelector.select(key);
+                // Skip the entry if it's not for current active consumer.
                 if (consumer == null || currentConsumer != consumer) {
+                    entry.release();
                     iterator.remove();
                 }
             }