[cleanup] Remove unused config autoShrinkForConsumerPendingAcksMap (apache#24315)

(cherry picked from commit 610060e)

Author: dao-jun

pulsar-broker-common/src/main/java/org/apache/pulsar/broker/ServiceConfiguration.java

@@ -932,14 +932,6 @@ The max allowed delay for delayed delivery (in milliseconds). If the broker rece
     )
     private boolean isAllowAutoUpdateSchemaEnabled = true;
 
-    @FieldContext(
-            category = CATEGORY_SERVER,
-            doc = "Whether to enable the automatic shrink of pendingAcks map, "
-                    + "the default is false, which means it is not enabled. "
-                    + "When there are a large number of share or key share consumers in the cluster, "
-                    + "it can be enabled to reduce the memory consumption caused by pendingAcks.")
-    private boolean autoShrinkForConsumerPendingAcksMap = false;
-
     @FieldContext(
         category = CATEGORY_SERVER,
         dynamic = true,