New sortBy() collection method added

[techmahedy]

Added sortBy() and sortByDesc() methods to Collection class

Example usage

// Sort users by age ascending
$sorted = $users->sortBy('age');

// Sort by age descending
$sorted = $users->sortByDesc('age');

// Sort with callback
$sorted = $users->sortBy(fn($user) => strlen($user['name']));

// Sort with numeric comparison
$sorted = $items->sortBy('price', SORT_NUMERIC);