Test errors when running `npm run test` on latest main branch

### What happened?

After pulling the latest `main` branch and performing a clean build, several test cases fail during npm run test. **Some tests throw errors or fail unexpectedly.**

I verified that my Cesium ion access token is valid, so the issue does not appear to be related to authentication.

### Reproduction steps

1. `npm run clean -dtx` and `git clean -dxf`
2. `npm install` and `npm run build`
3. `npm run test`
...

### Sandcastle example

_No response_

### Environment

Browser: `Chrome 141.0.7390.67`
CesiumJS Version: `1.134.0`
Operating System:

`OS Name: Microsoft Windows 11 Enterprise`

`OS Version: 10.0.26100 N/A Build 26100`

Reproduce the report on the latest main branch using npm run clean -dtx, git clean -dxf, npm install, npm run build, and npm run test. Inspect the resulting test errors and failures to identify their causes; done means the affected tests pass after a clean build without relying on authentication changes.

Written by the indexing model from the issue text.