[Fix](thrift api) column should be converted if const before serializ…

…e to arrow format (apache#26111)

```
select null;
```

The above sql from thrift api will cause crash in `write_column_to_arrow` since it's column const,
we should convert to full column

be/src/util/arrow/block_convertor.cpp

@@ -388,8 +388,9 @@ Status FromBlockConverter::convert(std::shared_ptr<arrow::RecordBatch>* out) {
             return to_doris_status(arrow_st);
         }
         _cur_builder = builder.get();
+        auto column = _cur_col->convert_to_full_column_if_const();
         try {
-            _cur_type->get_serde()->write_column_to_arrow(*_cur_col, nullptr, _cur_builder,
+            _cur_type->get_serde()->write_column_to_arrow(*column, nullptr, _cur_builder,
                                                           _cur_start, _cur_start + _cur_rows);
         } catch (std::exception& e) {
             return Status::InternalError("Fail to convert block data to arrow data, error: {}",