[Request]: [SLOs] Update SLO privilege model docs

[dominiqueclarke]

What documentation page is affected

https://www.elastic.co/guide/en/observability/current/slo-privileges.html

What change would you like to see?

The SLO privilege model was updated for 8.16.0.

In particular, there is no longer a requirement for SLO editor users to have cluster privileges manage_transform and manage_ingest_pipelines.

Additionally, the correct index privileges were added to the Observability editor role. Therefore, users can now choose to either use the editor role or create a custom role to grant index privileges to SLO users.

The required index privileges are as follows

Editor user

.slo-observability-*: `read`, `view_index_metadata`, `write`, `manage`

Viewer user

.slo-observability-*: `read`, `view_index_metadata`

### Additional info

_No response_

[eedugon]

Proposed changes to the doc (already working on them):

• Change the names of the roles (SLO All and SLO Read) to SLO Editor and SLO Viewer.
• Update the permissions needed for both types of roles to match the new values.
• Update screenshots.

Add the information about the editor built-in role being another option to grant SLO Editor permissions to the users.

Any thoughts?

[eedugon]

PR draft started here: #4300

[eedugon]

@dominiqueclarke , would we need to update anything in the serverless documentation related with this issue?

Based on the doc https://www.elastic.co/docs/current/serverless/observability/create-an-slo it's mentioned that The Admin role or higher is required to create SLOs., so I would say we don't need to change anything at Serverless documentation side.

By the way, is the previous statement accurate for serverless? Shouldn't Editor be enough based on the explanations from https://www.elastic.co/docs/current/serverless/general/assign-user-roles#observability ? (sorry for the offtopic).

[dominiqueclarke]

@eedugon

is the previous statement accurate for serverless? Shouldn't Editor be enough based on the explanations from

You are correct. We should update the serverless docs to mention The Editor role or higher is required to create SLOs, rather than Admin.

[eedugon]

thanks @dominiqueclarke : I have updated also the serverless doc in the mentioned PR