With fancy splash dashboard centering breaks when changing font size.

### What did you expect to happen?

With a fancy splash image. Doom dashboard text/image centering breaks when changing font size. Image sizing is also not consistent.

Expected centering of the buffer text/image to continue working after font size changes.

### What actually happened?

`s--` until it won't reduce font size. _(font too small warning)_

`s-+s` once and the dashboard `*doom*` buffer contents shift to the right, out of view.

### Describe your attempts to resolve the issue

When the frame is resized the centering is corrected.

### Steps to reproduce

Steps to reproduce.

1. Set a fancy splash image.
2. Visit the `*doom*` buffer.
3. call `(+doom/decrease-font-size)` until it won't reduce font size.
4. call `(+doom/increase-font-size)` once
5. The buffer contents shift to the right, out of view.
6. During resizing font, the image resize is inconsistent.

### System Information

https://pastebin.com/HRjwbZCR