Fix test

Author: alamb

datafusion/core/src/datasource/physical_plan/parquet/statistics.rs

@@ -874,10 +874,11 @@ impl<'a> StatisticsConverter<'a> {
     where
         I: IntoIterator<Item = &'a RowGroupMetaData>,
     {
-        let data_type = self.arrow_field.data_type();
-
         let Some(parquet_index) = self.parquet_index else {
-            return Ok(self.make_null_array(data_type, metadatas));
+            let num_row_groups = metadatas.into_iter().count();
+            return Ok(Arc::new(UInt64Array::from_iter(
+                std::iter::repeat(None).take(num_row_groups),
+            )));
         };
 
         let null_counts = metadatas