compilation fix

Author: jepett0

ydb/core/kqp/provider/yql_kikimr_exec.cpp

@@ -1519,7 +1519,7 @@ class TKiSinkCallableExecutionTransformer : public TAsyncCallbackTransformer<TKi
                     for (const auto& indexSetting : listNode) {
                         auto name = indexSetting.Name().Value();
                         if (name == "indexName") {
-                            alterIndex->set_name(indexSetting.Value().Cast<TCoAtom>().Value());
+                            alterIndex->set_name(indexSetting.Value().Cast<TCoAtom>().StringValue());
                         } else if (name == "tableSettings") {
                             auto tableSettings = indexSetting.Value().Cast<TCoNameValueTupleList>();
                             for (const auto& tableSetting : tableSettings) {