datashard owns /ydb/core/kqp/ut/indexes/ (#17558)

Author: kunga

.github/CODEOWNERS

@@ -16,6 +16,7 @@
 /ydb/core/kqp/ @ydb-platform/qp
 /ydb/core/kqp/ut/federated_query @ydb-platform/fq
 /ydb/core/kqp/ut/olap/ @ydb-platform/cs
+/ydb/core/kqp/ut/indexes/ @ydb-platform/qp @ydb-platform/datashard
 /ydb/core/public_http/ @ydb-platform/fq
 
 /ydb/docs/ @ydb-platform/docs