Query API key information API only accepts "aggs" and not "aggregations"

[l-trotta]

Elasticsearch Version

8.13.0

Installed Plugins

No response

Java Version

bundled

OS Version

elasticsearch cloud

Problem Description

Query API key information API returns:
[query_api_key_request_payload] unknown field [aggregations]

when called using aggregations instead of aggs, in the main aggregation (while the sub aggregations accept both).

Here's the line where we could see that it only accepts aggs.

This is a problem for the client libraries since all other aggregations accept both names.

Steps to Reproduce

POST /_security/_query/api_key
{
  "size": 0,
  "aggregations": {
    "keys_by_username": {
      "composite": {
        "sources": [ { "usernames": { "terms": { "field": "username" } } } ]  
      },
      "aggregations": {
        "expires_soon": {
          "filter": {
            "range": { "expiration": { "lte": "now+30d/d" } }  
          },
          "aggregations": {
            "key_names": { "terms": { "field": "name" } }
          }
        }
      }
    }
  }
}

Logs (if relevant)

No response

[elasticsearchmachine]

Pinging @elastic/es-security (Team:Security)

[l-trotta]

Forgot to mention: this issue is related to PR #104895, and like issue 106817 it prevents the strongly typed clients from supporting the new feature introduced in the PR. @albertzaharovits could you please take a look?