Create an E2E test that starts with an empty canvas

Will the front end folks determine the priority. Though the problem with an empty canvas discovered in #3472299-20: Update default config to make a fresh install result in an XB UI with an empty canvas → was actually a backend issue.

Bumping to because without it, our E2E tests do not cover the full spectrum of typical use.

Plus, it already slowed velocity down once before — even though the root cause was a simple back-end fix.

Hit us again #3485937-10: Drag and drop in the preview not working correctly →

Automatically closed - issue fixed for 2 weeks with no activity.