check vector access (#7474)

Author: uzhastik

ydb/services/metadata/ds_table/accessor_snapshot_base.cpp

@@ -34,6 +34,7 @@ void TDSAccessorBase::Handle(NRequest::TEvRequestResult<NRequest::TDialogYQLRequ
         Y_ABORT_UNLESS(it != CurrentExistence.end());
         Y_ABORT_UNLESS(it->second);
         if (it->second == 1) {
+            Y_ABORT_UNLESS((int)replyIdx < qResult.result_sets().size());
             *qResultFull.add_result_sets() = std::move(qResult.result_sets()[replyIdx]);
             ++replyIdx;
         } else {