Indentation and generated path fix

What does this MR do?

Minor fixes for the CI tunnel docs

• can not write to $HOME. Changing the generated path to $CI_PROJECT_DIR/.kubeconfig.agent.yaml
• specifying the generated kubeconfig in the path to make sure we use that context
• fixed indentation

Related issues

This is a follow up / fix for !63698 (merged).

Author's checklist

• Follow the Documentation Guidelines and Style Guide.
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