branch-2.1: [fix](group commit)Fix replay wal fail problem on agg state type #49081 (#49143)

Cherry-picked from #49081

Co-authored-by: huanghaibin <huanghaibin@selectdb.com>

fe/fe-core/src/main/java/org/apache/doris/tablefunction/ExternalFileTableValuedFunction.java

@@ -351,6 +351,7 @@ public abstract class ExternalFileTableValuedFunction extends TableValuedFunctio
             for (int i = 0; i < tableColumns.size(); i++) {
                 Column column = new Column(tableColumns.get(i).getName(), tableColumns.get(i).getType(), true);
                 column.setUniqueId(tableColumns.get(i).getUniqueId());
+                column.setIsAllowNull(true);
                 fileColumns.add(column);
             }
             return fileColumns;