Fix validation extensions

[frknakk]

$request->validate([
	'vat_id' => [new \Danielebarbaro\LaravelVatEuValidator\Rules\VatNumberFormat()],
]);

Using rules as object works

---

$request->validate([
	'vat_id' => 'vat_number_format',
]);

But using rules as string shortcut does not work

---

Problem

// VatValidatorServiceProvider.php
Validator::extend('vat_number_format', static function ($attribute, $value, $parameters, $validator): void {
	$rule = new VatNumberFormat();
	$rule->validate($attribute, $value, static fn (string $message = null): null => null);
});

The function does the validation, but just completely ignores the result. It has to return the validation result as boolean.