refactor: import FQCNs

[paulbalandan]

Description
Import them in use statements.

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[neznaika0]

The import is regulated by the cs rules. It seems they intentionally allow FQCN in the code.

[paulbalandan]

This is caused by the import_symbols option of fully_qualified_strict_types rule to be set to false. That was a new option though so that's why is not reflected here.