fix: Let Edge to send fetch requests using default config

[kamilogorek]

Fixes #1233

We add referrer because this comment #1177 (comment)

However, there's no easy way to test this behavior, as:

• mocking fetch won't call it's native implementation, therefore not throw an error
• spying on fetch won't modify response object, and without it, we'll always jump into onError handler because we get no ok in resp data

I'm not really convinced if this is a good idea... It just feels odd, but I cannot think of any simple, yet an acceptable solution to this issue.

Thoughts?

[HazAT]

I guess this is fine and probably the only thing we could do here.
Even though I am not sure if we still require referrer on the server but we can't force people to update their server so we have to live with it.