[8.4](backport #1106) Remove experimental warning log in upgrade command

[mergify]

This is an automatic backport of pull request #1106 done by Mergify.

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[elasticmachine]

💔 Build Failed

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Build stats

• Start Time: 2022-09-08T14:47:24.854+0000

• Duration: 15 min 52 sec

Test stats 🧪

Test	Results
Failed	0
Passed	4927
Skipped	17
Total	4944

Steps errors

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Google Storage Download

• Took 1 min 20 sec . View more details here
• Description: [2022-09-08T14:52:09.704Z] [Google Cloud Storage Plugin] Found 1 files to download from pattern: gs:

💚 Flaky test report

Tests succeeded.

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[elasticmachine]

🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	97.333% (73/75)	👍
Files	68.996% (158/229)	👍
Classes	69.095% (313/453)	👍
Methods	53.034% (874/1648)	👍
Lines	39.194% (9450/24111)	👎 -0.038
Conditionals	100.0% (0/0)	💚

[cmacknz]

/test

[cmacknz]

Failure is unrelated, merging.

There is a discussion about the underlying reason for the failure in #1120