[php-src] Issue #20863: Unable to use getimagesize on HEIC/HEIF images

Issue: https://github.com/php/php-src/issues/20863
Author: earthiverse

### Description

I downloaded the heic from the pull request https://github.com/php/php-src/pull/18940, and that one *does* work, but none of the sample images I downloaded from https://heic.digital/samples/ work.

The following code:

```php
<?php

$dir = __DIR__;

$allowedExt = ['jpg', 'jpeg', 'heic', 'heif'];

foreach (new DirectoryIterator($dir) as $file) {
    if ($file->isDot() || !$file->isFile()) {
        continue;
    }
    
    $ext = strtolower($file->getExtension());
    if (!in_array($ext, $allowedExt, true)) {
        continue;
    }
    
    $path = $file->getPathname();
    $info = @getimagesize($path);
    
    if ($info === false) {
        echo "Failed: $path\n";
        continue;
    }
    
    [$width, $height, $type] = $info;
    echo "$path => {$width}x$height\n";
}
```

Resulted in this output:
```
Failed: /Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/soundboard.heic
Failed: /Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/shelf-christmas-decoration.heic
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/test4pix.heic => 54x84
Failed: /Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/sewing-threads.heic
Failed: /Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/chef-with-trumpet.heic
Failed: /Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/childrens-show-theater.heic
Failed: /Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/classic-car.heic
Failed: /Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/greyhounds-looking-for-a-table.heic
```

But I expected this output instead:
```
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/soundboard.heic => 4000x3000
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/shelf-christmas-decoration.heic => 4000x3000
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/test4pix.heic => 54x84
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/sewing-threads.heic => 4000x3000
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/chef-with-trumpet.heic => 4032x3024
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/converted.jpeg => 8736x5856
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/childrens-show-theater.heic => 4032x3024
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/classic-car.heic => 3024x4032
/Users/earthiverse/Sites/media-store/tests/Codeception/Support/Data/images/heif/greyhounds-looking-for-a-table.heic => 3024x4032
```


### PHP Version

```plain
PHP 8.5.1 (cli) (built: Dec 16 2025 15:59:07) (NTS)
Copyright (c) The PHP Group
Built by Shivam Mathur
Zend Engine v4.5.1, Copyright (c) Zend Technologies
    with Xdebug v3.5.0, Copyright (c) 2002-2025, by Derick Rethans
    with Zend OPcache v8.5.1, Copyright (c), by Zend Technologies
```

### Operating System

MacOS Tahoe 26.2