[8.x] Risk score calculation for closed alerts (backport #6271)

[mergify]

Resolves #6254.

Previews

ESS:

• Entity risk scoring | How is risk score calculated
• Turn on the risk scoring engine | Turn on the latest risk engine

Serverless

• Entity risk scoring | How is risk score calculated
• Turn on risk scoring | Turn on the risk engine

---

This is an automatic backport of pull request #6271 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 19e3484 has failed:

On branch mergify/bp/8.x/pr-6271
Your branch is up to date with 'origin/8.x'.

You are currently cherry-picking commit 19e3484f.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   docs/advanced-entity-analytics/entity-risk-scoring.asciidoc
	modified:   docs/advanced-entity-analytics/images/preview-risky-entities.png
	modified:   docs/advanced-entity-analytics/images/turn-on-risk-engine.png
	modified:   docs/advanced-entity-analytics/turn-on-risk-engine.asciidoc

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/serverless/advanced-entity-analytics/entity-risk-scoring.asciidoc
	deleted by us:   docs/serverless/advanced-entity-analytics/turn-on-risk-engine.asciidoc
	deleted by us:   docs/serverless/images/turn-on-risk-engine/preview-risky-entities.png
	deleted by us:   docs/serverless/images/turn-on-risk-engine/turn-on-risk-engine.png

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[github-actions]

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