Add missing codegen_name annotations to all value bodied responses

[flobernd]

In the .NET client, these value-type bodies will be wrapped in a common response type like e.g.:

public partial class EsqlQueryResponse : 
    ElasticsearchResponse
{
    public byte[] Data { init; }
}

In order to properly auto-generate the required body property (e.g. Data in this case) with a meaningful name, all of these bodies must be annotated with codegen_name attributes.

It would be nice having a compiler check for this rule in the future.

[swallez]

Let me check if this causes breaking changes on the Java client...

[swallez]

LGTM, but I'd like @Anaethelion to also have a look from the Go client perspective.

[Anaethelion]

LGTM, no impact on my part.

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
cluster.remote_info	🟢	3/3	3/3
esql.query	🔴	156/162	7/162
get_source	🟢	18/18	18/18
ilm.get_lifecycle	🟢	8/8	8/8
indices.disk_usage	🟢	5/5	5/5
indices.downsample	🟢	1/1	1/1
indices.get_alias	🔴	83/83	71/83
indices.get_field_mapping	🔴	15/15	14/15
indices.get_mapping	🔴	91/91	87/91
indices.get_settings	🔴	56/56	54/56
indices.get_template	🟢	30/30	30/30
indices.get	🟢	53/53	53/53
indices.promote_data_stream	⚪	Missing test	Missing test
indices.recovery	🟢	9/9	9/9
indices.resolve_cluster	🔴	10/12	12/12
ingest.get_pipeline	🔴	22/22	21/22
logstash.get_pipeline	⚪	Missing test	Missing test
ml.preview_datafeed	🔴	10/17	17/17
rollup.get_rollup_caps	🟢	3/3	3/3
rollup.get_rollup_index_caps	🟢	7/7	7/7
search_application.get_behavioral_analytics	⚪	Missing test	Missing test
search_mvt	🔴	34/34	0/34
searchable_snapshots.clear_cache	🟢	1/1	1/1
security.delete_privileges	🟢	6/6	6/6
security.get_privileges	🟢	12/12	12/12
security.get_role_mapping	🔴	18/18	10/18
security.get_role	🟢	20/20	20/20
security.get_service_accounts	⚪	Missing test	Missing test
security.get_user	🟢	25/25	25/25
security.put_privileges	🟢	10/10	10/10
slm.get_lifecycle	🟢	16/16	16/16

You can validate these APIs yourself by using the make validate target.