Example data fits Sphinx Gallery's image dimensions (#1246)

**Title:**
Adapt example data in demo to fit Sphinx Gallery's image dimensions

**Summary:**
Sphinx Gallery renders single images at 640px by 480px. Adjusting the
layout of the example data to better fit these dimensions and reduce
white space.

**Relevant references:**
https://app.shortcut.com/xanaduai/story/76532

### Before:

![image](https://github.com/user-attachments/assets/e7ead268-2ffd-4b99-9145-dedc0a44237d)

### After:

![image](https://github.com/user-attachments/assets/30113eb4-2e2d-4750-9598-816c226ee503)