Remove redundant get Stats call (#160)

* fix get stats twice

* empty

* empty

Author: chaoqin-li1123

src/main/scala/org/apache/spark/sql/pulsar/PulsarHelper.scala

@@ -539,8 +539,7 @@ class PulsarAdmissionControlHelper(adminUrl: String, conf: ju.Map[String, Object
     val startLedgerId = getLedgerId(startMessageId)
     val startEntryId = getEntryId(startMessageId)
     val stats = pulsarAdmin.topics.getInternalStats(topicPartition)
-    val ledgers = pulsarAdmin.topics.getInternalStats(topicPartition).ledgers.
-      asScala.filter(_.ledgerId >= startLedgerId).sortBy(_.ledgerId)
+    val ledgers = stats.ledgers.asScala.filter(_.ledgerId >= startLedgerId).sortBy(_.ledgerId)
     // The last ledger of the ledgers list doesn't have .size or .entries
     // properly populated, and the corresponding info is in currentLedgerSize
     // and currentLedgerEntries