message: solved TODOs
diff: @@ -190,12 +190,11 @@ static void UnnestVector(UnifiedVectorFormat &child_vector_data, Vector &child_v
  auto &child_vector_entries = StructVector::GetEntries(child_vector);
  auto &result_entries = StructVector::GetEntries(result);
  - // TODO: still don't completely understand why this is necessary
  + // set the validity mask for the 'outer' struct vector before unnesting its children
  UnnestValidity(child_vector_data, start, end, result);
  for (idx_t i = 0; i < child_vector_entries.size(); i++) {
  UnifiedVectorFormat child_vector_entries_data;
  - // TODO: is list_size the correct length?
  child_vector_entries[i]->ToUnifiedFormat(list_size, child_vector_entries_data);
  UnnestVector(child_vector_entries_data, *child_vector_entries[i], list_size, start, end,
  *result_entries[i]);
  