[REQUEST]: Improve 'Reset the Elastic Cloud policy' step in Fleet Agent migration docs

[gergoabraham]

Description

Docs: https://www.elastic.co/guide/en/fleet/current/migrate-elastic-agent.html#migrate-elastic-agent-reset-policy

When performing Agent migration in QA console between two hosted deployments, I experienced two issues regarding the step called Reset the Elastic Cloud policy:

1. The step says to open Management -> Dev tools, and paste the given curl commands there. However, this does not work properly (I think because headers cannot be set in Dev console), so instead I needed to send the request from a terminal by updating the curl command with the precise URL and credentials. I think we should remove the suggestion to use the Dev console as it's misleading.

2. When I performed this step, I had an issue that the Fleet agent disappeared, and Kibana indicated that Fleet is unhealthy.

before and after:

We should include a note, that if the user experiences this issue, they can restart the Integration server of the deployment, and that fixes the problem by enrolling a new Agent for the Cloud Agent policy.

Resources

here's a slack thread where the workaround for restarting the integration server comes from: https://elastic.slack.com/archives/CNMNXV4RG/p1707207063090799

Collaboration

The documentation team will investigate the issue and create the initial content.

Point of contact.

Main contact: @gergoabraham

Stakeholders:

[kilfoyle]

Thanks for opening this @gergoabraham! And by the way, your deployment names are making me hungry. :-)

I've opened up #923 to fix up the docs. Please let me know if I've missed anything.

[gergoabraham]

@kilfoyle wow, that was fast. thanks a lot! and sorry for causing hunger 😀