feat!: Testing/Allowing PHP 8.1

[podarok]

Original Issue, this PR is going to fix: https://openy.atlassian.net/browse/MAINTAIN-220

Make sure these boxes are checked before asking for review of your pull request - thank you!

If there is a new feature or this is a bug fix - use 9.x-2.x branch. We'll tag for release if the bug is critical asap or tag for release next bug fix release until critical issue arrived.

Steps for review

• Global system drush should be of version 8.4.8.
• Install latest robo https://github.com/consolidation/robo#installing .
• Enable proper error_reporting for 8.1 php cli PHP 8.1 giving errors and warnings consolidation/robo#1071 (comment)
• [ ]

General checks

• All coding styles are fulfilled and there are no any issues reported by CodeSniffer. See Code of Conduct.
• Try to use Conventional commit messages accordingly to the standard https://www.conventionalcommits.org/en/v1.0.0/#specification
• Documentation has been updated according to PR changes.
• Steps for review have been provided according to PR changes.
  
• Make sure you've provided all necessary hook_update_N to support upgrade path.
• Make sure your git email is associated with account on drupal.org, otherwise you won't get commits there.
  
• If you would like to get credits on drupal.org, check documentation.

Thank you for your contribution!

[gundevel]

Build comment file:

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[podarok]

retest this please

[gundevel]

Build comment file:

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Test PASSed.
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[gundevel]

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[gundevel]

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