The title is not displayed when used with titleRow

I tried the example with the title and the titleRow. An h1 is correctly generated but no title is displayed.

```
---
title: This will now be the heading
titleRow: true
---

This content can now be styled/positioned independent of the title,
because it will be in a separate grid cell.
```


(nice them by the way)

Reproduce the provided Slidev example using both title and titleRow in the vuetiful theme, then inspect the generated slide to trace why the title is absent. Done means the title text is displayed while the content remains in its separate grid cell.

Written by the indexing model from the issue text.