minor #44835 Suppress psalm error for UndefinedDocblockClass for PHP 8.1 classes (ogizanagi)

This PR was merged into the 4.4 branch.

Discussion
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Suppress psalm error for UndefinedDocblockClass for PHP 8.1 classes

| Q             | A
| ------------- | ---
| Branch?       | 4.4 <!-- see below -->
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tickets       | https://github.com/symfony/symfony/pull/44831#discussion_r776204831 <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License       | MIT
| Doc PR        | N/A

Same as https://github.com/symfony/symfony/pull/43050 for inlined docblock comments (mainly `class-string<FQCN>`)

Commits
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dbc3eea9 Suppress psalm error for UndefinedDocblockClass for PHP 8.1 classes