[Dataset quality] Document failure store privileges

[yngrdyn]

Description

In https://github.com/elastic/logs-dev/issues/182 we introduced a banner to let users know they are missing some privileges to access failure store. The idea is to document what is needed in order to access that information.

We could also reference Failure store official documentation from there.

Resources

This feature is part of [project] Expose failure store data.
The changes are tracked in the issues of the project.

Which documentation set does this change impact?

Stateful and Serverless

Feature differences

The feature is identical in both

What release is this request related to?

8.17
sooner for serverless

Collaboration model

The documentation team

Point of contact.

Main contact: @yngrdyn

Stakeholders: @gbamparop