Document how to troubleshoot job token errors

What does this MR do and why?

Related to #339862 (closed)

In this MR we document how to troubleshoot errors related to CI job token usage. We provide some examples to be discoverable by search and describe what to check / do to ensure the job token is used properly.

Screenshots or screen recordings

These are strongly recommended to assist reviewers and reduce the time to merge your change.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.