Stateless (Goldilocks) API ignores ToS / PP

Easy to revert if we need to, but let's start by keeping the Goldilocks surface area as absolutely minimal as possible. More discussion in the issue below:

Related to #4134
Hmm, I was thinking we could use the existing test file to ensure that ToS/PP would fail if passed when rp_api == 'stateless'. That might still be useful?

But I think what we really want is to probably split this file into the BrowserSupport piece and the "really load Persona" pieces (internalWatch, internalRequest, the public API), and test both separately, the former with UA strings from Browserscope via npm useragent package, the latter with a fake WinChan. I'll just do this in a separate bug, though :-)