Fix SVG mime type in Symfony

AppKernel.php

<?php

declare(strict_types=1);

use AppBundle\HttpFoundation\File\MimeType\ErrataMimeTypeGuesser;
use Symfony\Component\Config\Loader\LoaderInterface;
use Symfony\Component\HttpFoundation\File\MimeType\FileBinaryMimeTypeGuesser;
use Symfony\Component\HttpFoundation\File\MimeType\FileinfoMimeTypeGuesser;
use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser;
use Symfony\Component\HttpKernel\Kernel;

class AppKernel extends Kernel
{
    private $errataMimeTypeGuesserRegistered = false;

    /**
     * {@inheritdoc}
     */
    public function boot(): void
    {
        $this->registerErrataMimeTypeGuesser();

        parent::boot();
    }

    /**
     * {@inheritdoc}
     */
    public function registerBundles(): array
    {
        // ...
    }

    /**
     * {@inheritdoc}
     */
    public function registerContainerConfiguration(LoaderInterface $loader): void
    {
        // ...
    }

    private function registerErrataMimeTypeGuesser(): void
    {
        if ($this->errataMimeTypeGuesserRegistered) {
            return;
        }

        $decorated = null;

        if (
          FileBinaryMimeTypeGuesser::isSupported() &&
          null !== shell_exec('command -v file') // https://github.com/symfony/symfony/pull/26886
        ) {
            $decorated = new FileBinaryMimeTypeGuesser();
        } elseif (FileinfoMimeTypeGuesser::isSupported()) {
            $decorated = new FileinfoMimeTypeGuesser();
        }

        if (null !== $decorated) {
            MimeTypeGuesser::getInstance()->register(new ErrataMimeTypeGuesser($decorated));
        }

        $this->errataMimeTypeGuesserRegistered = true;
    }
}

ErrataMimeTypeGuesser.php

<?php

declare(strict_types=1);

namespace AppBundle\HttpFoundation\File\MimeType;

use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface;

class ErrataMimeTypeGuesser implements MimeTypeGuesserInterface
{
    private $decorated;

    public function __construct(MimeTypeGuesserInterface $decorated)
    {
        $this->decorated = $decorated;
    }

    /**
     * {@inheritdoc}
     */
    public function guess($path): ?string
    {
        $mimeType = $this->decorated->guess($path);

        if ('image/svg' === $mimeType) {
            $mimeType = 'image/svg+xml';
        }

        return $mimeType;
    }
}