presenter image is not working on non default base directory

[unotovive]

If base directory changes from default, presenter image is not working.

In the original repository, the URL is converted based on the Base Directory when using the image.

https://github.com/slidevjs/themes/blob/f0ead018f3c4a2e3dc433e8526e2f5a3205d8b29/packages/theme-apple-basic/layoutHelper.ts#L6

Here we need to do the same with the following line

https://github.com/alvarosaburido/slidev-theme-penguin/blob/92084073838971cb079c0d8f1b7f5c7b2624aed3/layouts/presenter.vue#L37