[Request]: Update the guide to Switch from APM Server standalone to Fleet managed on ECH

[simitt]

Description

What

When a user wants or needs to switch from a to the Fleet managed version, they can do so via Kibana. However with the refactoring of the Kibana Observability page, the public guide how to reach the migration option is outdated.

The guide needs to be changed from :

In Kibana, go to the Applications app and click Settings → Schema.

to :

In Kibana, go to Observability -> APM -> Services app and click on Settings → Schema.

When

The UI refactoring was done throughout 8.x lifecycle, so this is currently a bug and should be done at earliest convenience.

Why

The current guide is not valid anymore.

Resources

Link to the public guide: https://www.elastic.co/guide/en/observability/current/apm-integration-upgrade-steps-ess.html#apm-integration-upgrade-ess-2

This issue was reported in https://github.com/elastic/sdh-control-plane/issues/9144#issuecomment-2706879142.

Which documentation set does this change impact?

Stateful only

Feature differences

The feature only exists in Stateful.

What release is this request related to?

N/A

Collaboration model

The documentation team

Point of contact.

Main contact: @simitt

Stakeholders: @elastic/obs-ds-intake-services @elastic/obs-ux-infra_services-team