Improve Arkose logging and documentation

What does this MR do and why?

• Resolves gitlab-com/gl-infra/production-engineering#27462 (moved) by improving Arkose logging and documentation
• Add more details to the Arkose documentation on how to triage
• Improve Arkose logging by removing double-ups and consolidating them with an Arkose prefix
• We have Kibana alerting set-up for Arkose which posts in the #feed_identity_verification_alerts channel, but it didn’t work as expected because it’s only set-up to track when Arkose token verification returns an error. In this case, Arkose was not returning an error, but instead returning an invalid token message — so we’ll update our alert to include both scenarios. Once this MR is merged, I'll update that.

References

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