branch-2.1: [fix](txn) Restart fe after commit txn causes loadedTblIndexes lossing #50123 (#50206)

Cherry-picked from #50123

Co-authored-by: Uniqueyou <wangyixuan@selectdb.com>

fe/fe-core/src/main/java/org/apache/doris/transaction/TransactionState.java

@@ -274,6 +274,7 @@ public class TransactionState implements Writable {
     // this map should be set when load execution begin, so that when the txn commit, it will know
     // which tables and rollups it loaded.
     // tbl id -> (index ids)
+    @SerializedName(value = "loadedTblIndexes")
     private Map<Long, Set<Long>> loadedTblIndexes = Maps.newHashMap();
 
     /**