CDK: Add tests for the HTttpStream to check authenticator call on each request

[htrueman]

Tell us about the problem you're trying to solve

We need to test that HTttpStream correctly calls the authenticator on every request.

Describe the solution you’d like

Add new tests to test_http.py which will call the request and check if the authenticator was called correctly. As result the authenticator should modify the request (e.g. update request headers).

Describe the alternative you’ve considered or used

None

Additional context

This issue continues the #5731 PR, where we added the requests native auth support.

Are you willing to submit a PR?

Yes, I am.