[10.x] Change Arr::sortRecursiveDesc() method to static.

[gkisiel]

This PR makes the Arr::sortRecursiveDesc() method static, which it should be.

[driesvints]

Please add more reasoning why this is needed.

[gkisiel]

Using the folllowing code

$array = [
    ['Roman', 'Taylor', 'Li'],
    ['PHP', 'Ruby', 'JavaScript'],
    ['one' => 1, 'two' => 2, 'three' => 3],
];
 
$sorted = Arr::sortRecursiveDesc($array);

causes PHP parser error:

Non-static method Illuminate\Support\Arr::sortRecursiveDesc() cannot be called statically

The Arr::sortRecursiveDesc() method references another Arr::sortRecursive() method, which is a static method.

Edit: Was wrong example.