Make it work with PHP 8.0

[shemgp]

method_exists requires first parameter to be object or string now and won't accept a null parameter

[stevebauman]

Thanks @shemgp! Can you make this into a single if statement? For example:

protected function isTrashed()
{
    return $this->model
        ? method_exists($this->model, 'trashed') && $this->model->trashed()
        : false;
}

I will then merge the PR 👍