How to validate JSON in Laravel API regardless of parameters order?

I am making an iOS app with Alamofire as the HTTP Request handler, and in the iOS App, i want to send a JSON payload to a Laravel API server. More or less, the JSON structure looks like this:

{
    "test_data": "Any data is here",
    "another_data": "Another data is here"
}

Now, in my Laravel project, I've been implementing a validation rule, basically to validate that those 2 params in the JSON is required and in a type of String. Here's my code to implement the validator:

$validator = Validator::make($request->all(), [
    'test_data' => 'required|string',
    'another_data' => 'required|string'
]);

if ($validator->fails()) {
    return redirect()->route('dataNotComplete');
}

The confusion is that this works, but it only works in order. Hence, if the JSON structure becomes flipped like this:

{
    "another_data": "Another data is here",
    "test_data": "Any data is here"
}

Validator will fails the test, even though the data is technically correct. How do I make the validator doesn't care about data ordering, or do another library exist for validating JSON specifically? I just want to validate the data of each params, not including the order of the data on the JSON Payload. Any thoughts or idea will be appreciated! Thank you!

P.S. I read from here that JSON order of parameters shouldn't matter, so that's that.