Testing "back in stock notfication" uses "price grid" instead of "stock grid" in preview mode

[rutgerrademaker]

Issue seems to be this part uses the "template" to determine the block
But in the module, the template is actually containing the id of the template.

https://github.com/yireo/Yireo_EmailTester2/blob/master/Model/Mailer/Variable/AlertGrid.php#L161

    private function getBlockClass(): string
    {
        if (strstr($this->template, 'stock')) {
            return Stock::class;
        }

        return Price::class;
    }

Maybe we can look up the actual template based upon this id, and then use the orig_template_code ?
This would work for catalog_productalert_email_stock_template and amxnotif_customer_notifications_stock_template

I might find some time for this one day, mainly posting this to get some feedback on a potential solution