fix: allocate much memory for residual vectors than needed (#3446)

Signed-off-by: BubbleCal <bubble-cal@outlook.com>

Author: BubbleCal

rust/lance-index/src/vector/residual.rs

@@ -91,9 +91,10 @@ where
             let c = &centroids_slice[part_id * dimension..(part_id + 1) * dimension];
             iter::zip(vector, c).map(|(v, cent)| *v - *cent)
         })
-        .exact_size(vectors.len() * dimension)
+        .exact_size(vectors.len())
         .collect::<Vec<_>>();
     let residual_arr = PrimitiveArray::<T>::from_iter_values(residuals);
+    debug_assert_eq!(residual_arr.len(), vectors.len());
     Ok(FixedSizeListArray::try_new_from_values(
         residual_arr,
         dimension as i32,