Remove event.original removal processors from ingest pipelines

[Alphayeeeet]

It seems that most of the checked integrations have a removal processor for event.original (except if it contains the preserve tag) in their pipelines.
In the other way, the .fleet-final-pipeline also has this processor and runs after all integration pipelines (incl. the @Custom pipelines) have finished. If the integration has this removal, the @Custom pipeline cannot parse the original event anymore as it is not present in the event anymore.

I would suggest removing the removal processors from all integration ingest pipelines and forward the removal functionality into the fleet-final-pipeline where it belongs. In that case @Custom pipelines may parse the original event and can extract additional data or correct malformed parsing in the generic integrations (e.g. catalina.out in the Apache Tomcat integration):

[andrewkroh]

I think this is a good idea. I will occasional install a logs@custom pipeline that keeps the event.original when there is a pipeline failure so that I can debug it.

PUT _ingest/pipeline/logs@custom
{
  "processors": [
    {
      "append": {
        "field": "tags",
        "value": [
          "preserve_original_event"
        ],
        "allow_duplicates": false,
        "tag": "ctx.error?.message != null",
        "ignore_failure": true
      }
    }
  ]
}

And in order for this to work, I currently have to manually drop that remove processor from the managed pipelines.

[Alphayeeeet]

If that change would be approved, I maybe start working on this after my current PR has been merged.

[andrewkroh]

Relates #7636

[andrewkroh]

This work was partially completed through several pull requests. To finish this out, I think we should script the changes. We can review edits to each team's integrations separately to optimize the process. Basically the script needs to delete the remove processor for the event.original field and ensure that the integration requires at least >=8.11.0 (where the Fleet final pipeline changes were introduced).