Symfony version(s) affected: 4.4.4

Description
The DateIntervalNormalizerm throws a validation error while denormalizing a valid Duration string.

How to reproduce

// First, run "composer require symfony/serializer"
// Then, execute this file:
<?php
require_once __DIR__.'/vendor/autoload.php';

use Symfony\Component\Serializer\Normalizer\DateIntervalNormalizer;

$dateIntervalNormalizer = new DateIntervalNormalizer();

$dateIntervalNormalizer->denormalize('PT12H34M', 'DateInterval');

Possible Solution
The validation on line L105 expects that the Duration string have the full duration pattern (eg. 'P1Y1M1DT1H1M1S'), but the DateInterval class accepts a string like 'PT12H34M' (12 hour, 34 minutes) as a valid input.
The ISO8601 says that elements with value equals to zero can be omitted.
Also, while testing, I found that the validation done in line L137 have the same problem for the same reasons explained above.
The other solution would be change the regex to validate the input correctly.
The solution, IMHO, is to create the DateInterval object right at the top of the method, since DateInterval already validates the input in the constructor.

Additional context
PHP: 7.4.2 for Windows
OS: Windows 10 Pro (1909)