Consider Removing third-party pipeline invokation and definition from Nginx, Apache, AWS CloudTrail, Zeek integration

[herrBez]

In 2021, the third-party pipeline was introduced in elastic/integrations#545.
From my understanding, it was developed to integrate or collect logs from third-party sources (e.g., Splunk) into Elastic.
In 2025, we removed the third-party stream input from the same integration in elastic/integrations#14995.
However, the corresponding third-party ingest pipelines (and their references in the main pipeline) were not removed.
If these pipelines are no longer needed, the main pipeline is currently performing unnecessary checks.

I am opening this issue to ask whether it is expected to have these third-party ingest pipelines and invokations:

• Nginx
• Apache
• AWS CloudTrail
• Zeek

EXAMPLE

The NGINX Access pipeline is invoking the third-party pipeline here:

https://github.com/elastic/integrations/blob/685d79a58c5665422453dc57aeb4616f7317121d/packages/nginx/data_stream/access/elasticsearch/ingest_pipeline/default.yml#L5C3-L7C49

  - pipeline:
      if: ctx.message.startsWith('{')
      name: '{{ IngestPipeline "third-party" }}'

If the third-party pipeline should not exist in the first place, we can spare the first processor in the pipeline (and remove the invoked third-party pipeline)