Port "Improve shutdown logs" from 8.5 back to main

[mergify]

This is an automatic backport of pull request #1627 done by Mergify.
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Changes to be committed:
	new file:   changelog/fragments/1666789812-Improve-shutdown-logs.yaml

Unmerged paths:
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	both modified:   NOTICE.txt
	both modified:   go.mod
	both modified:   go.sum
	both modified:   internal/pkg/agent/application/actions/handlers/handler_action_settings.go
	both modified:   internal/pkg/agent/application/upgrade/upgrade.go
	both modified:   internal/pkg/agent/cmd/run.go

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[cmacknz]

We lost the changes in https://github.com/elastic/elastic-agent/pull/1618/files as part of the V2 merge. Bringing these changes forward from the 8.5 branch.

[elasticmachine]

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• Start Time: 2022-12-12T22:19:35.311+0000

• Duration: 17 min 31 sec

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Test	Results
Failed	0
Passed	4665
Skipped	13
Total	4678

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[cmacknz]

I think this is probably reversed, example from a recent 8.5.3 upgrade attempt

"Restarting after upgrade","new_version":"8.5.3","prev_version":"8.6.0",

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	98.333% (59/60)	👍
Files	69.082% (143/207)	👍
Classes	69.133% (271/392)	👍
Methods	53.983% (820/1519)	👍
Lines	39.129% (8878/22689)	👍 0.011
Conditionals	100.0% (0/0)	💚

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