test_suite causes problem with latest setuptools

We noticed setup error when pushing our app to Cloud Foundry:

```
note: This error originates from a subprocess, and is likely not a problem with pip.
 error: legacy-install-failure
 
 × Encountered error while trying to install package.
 ╰─> feedgen
```

Removing the `test_suite` from `setup.py` solve the issue.

**Details in**
- https://github.com/GSA/data.gov/issues/5228