Create an unreadable temp directory for testing PermissionError

Description

We used a random user's home directory for testing how a function behaves when we don't have read access. That directory no longer exists, making the test fail. This is hopefully more reliable than picking another username.

How Has This Been Tested?

CI

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the code style of this project.

Reviewers

@schmidtp @ahmedk