change test to slider for disk create

app/UI/Disk/Forms/UpdateForm.php

@@ -43,7 +43,7 @@ class UpdateForm extends BaseForm implements ClientArea
         logModuleCall(
             'proxmoxCloud',
             __FUNCTION__,
-            $this->fields['additionalDiskSize'],
+            parent::getFormData()['id'],
             'Debug',
             parent::getFormData()['size']
         );