TimothyBJacobs has created Issue #2729: castAttribute does not handle nullable immutable date times in laravel-mongodb. This Jira ticket was filed by alcaeus

Issue Text:

• Laravel-mongodb Version: 4.1.1
• PHP Version: 8.1
• Database Driver & Version: 6.0.13

Description:

The `castAttribute` method is overloaded in the base `Model` class. Unlike in the Core Laravel `hasAttributes` trait, it is missing handling for `null` values. See this code snippet from Laravel:

```php
if (is_null($value) && in_array($castType, static::$primitiveCastTypes))

{ return $value; }

```

Steps to reproduce

```php
class MyModel extends \MongoDB\Laravel\Eloquent\Model

{ protected $casts = [ 'my_date' => 'immutable_datetime', ]; }

$model = new MyModel();
$model->my_date; // Should be null, instead is current time.
```

Expected behaviour

`null` should be returned.

Actual behaviour

The current time is returned.