FXGLDefaultMenu::createTitleView - incorrect layout width calculation

```
        // the lazy font size may not have been computed by this point
        // so we need to listen for changes in layout bounds of text1 and text2

val textWidth = text.layoutBounds.width + text2.layoutBounds.width
```

https://github.com/AlmasB/FXGL/blob/43a1a24ac82b03ed733734c2c35ececb0bf5c4e2/fxgl/src/main/kotlin/com/almasb/fxgl/app/scene/FXGLDefaultMenu.kt#L199