CS fix: expand single-line stub methods in FormTypeClassValidatorTest #1581

Job	Run time
PHPUnit (Symfony NEXT 8.2) (PHP 8.5)	40s
Behat (Symfony 8.1) (PHP 8.5)	5m 16s
Behat (Symfony ^7.4) (PHP 8.5) (lowest dependencies)	3m 55s
Behat (Symfony NEXT 8.2) (PHP 8.5)	4m 30s
PHPUnit (Symfony 7.4) (PHP 8.5)	3m 59s
PHP-CS-Fixer (PHP 8.5)	16s
Behat (Symfony 7.4) (PHP 8.5)	5m 27s
PHPUnit (Symfony 8.1) (PHP 8.5)	53s
PHPUnit (Symfony ^7.4) (PHP 8.5) (lowest dependencies)	45s
	25m 41s

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