change test to slider for disk create

app/UI/Disk/Forms/UpdateForm.php

@@ -43,6 +43,7 @@ class UpdateForm extends BaseForm implements ClientArea
         $this->setProvider(new DiskProvider());
         $this->initFields();
         $this->loadDataToForm();
+        $this->getField('additionalDiskSize')['minValue']->setValue(20);
 
         logModuleCall(
             'proxmoxCloud',