Add callable support in sortByMany

[drequenagonzalez]

This change adds support for callable props exactly the same way like in Laravel Collections.

I've added it because I was getting an error using it like this:

$arr = [
    ['name' => 'ATest', 'age' => 34],
    ['name' => 'BTest', 'age' => 30],
    ['name' => 'ATest', 'age' => 36],
    ['name' => 'BTest', 'age' => 32],
]
|>sortBy([
    fn (array $a, array $b) => $a['name'] <=> $b['name'],
    fn (array $a, array $b) => $b['age'] <=> $a['age'],
]);

[sebastiandedeyne]

Looks good! Could you also include a test in your PR?

[drequenagonzalez]

@sebastiandedeyne Done! 🙌

[sebastiandedeyne]

Thanks!