[main](backport #3606) Changelog for 8.10.4

[mergify]

This is an automatic backport of pull request #3606 done by Mergify.
Cherry-pick of 22938b1 has failed:

On branch mergify/bp/main/pr-3606
Your branch is up to date with 'origin/main'.

You are currently cherry-picking commit 22938b10f3.
  (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:
	new file:   changelog/8.10.4.asciidoc
	new file:   changelog/8.10.4.yaml
	deleted:    changelog/fragments/1695289867-Secondary-fallback-for-package-signature-verification.yaml

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by them: changelog/fragments/1693427183-install-progress.yaml

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

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[elastic-sonarqube]

SonarQube Quality Gate

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

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💚 Build Succeeded

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Build stats

• Start Time: 2023-10-17T09:45:27.846+0000

• Duration: 28 min 53 sec

Test stats 🧪

Test	Results
Failed	0
Passed	6501
Skipped	59
Total	6560

💚 Flaky test report

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[elasticmachine]

🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	98.81% (83/84)	👍
Files	67.105% (204/304)	👍
Classes	65.719% (370/563)	👍
Methods	52.997% (1167/2202)	👍
Lines	39.288% (13604/34626)	👍
Conditionals	100.0% (0/0)	💚