change test to slider for disk create

app/UI/Disk/Forms/UpdateForm.php

@@ -54,6 +54,7 @@ class UpdateForm extends BaseForm implements ClientArea
     {
         //entity id
         $this->addField(new Hidden("id"));
+        $this->dataProvider->read();
         //size
         $this->resourceManager = new ResourceManager();
         $field = new Range('additionalDiskSize', $this->data['size'], $this->resourceManager->disk()->free());