[BUG] Fix visualization error in cg.visualize

The cg.visualize function currently fails with a runtime error. The issue may be related to a missing or misconfigured dependency during the pyppeteer installation, causing the browser to exit unexpectedly.

Error message:
```bash
pyppeteer.errors.BrowserError: Browser closed unexpectedly
```

Temporary fix: Use draw_ascii() method as replacement for now.