PutIndexTemplateRequest doesn't support allow_custom_routing attribute for dataStream object

[voron86]

Java API client version

8.15.1

Java version

kotlin 2.0

Elasticsearch Version

8.x

Problem description

To be able to use custom routing with data streams we need to be able to put an index template with the allow_custom_routing: true attribute in the data_stream object. We use Kotlin service to configure indexes and streams. Due to lack of the attribute support in ElasticsearchAsyncClient::PutIndexTemplateRequest we should use low level rest client for the operation what is a bit inconvenient.
Is it possible to add the attribute support?
BTW, I see it's already supported in the response data objects.