Clarify `network.authRequired` handling when interception is not enabled

[Lightning00Blade]

An example User journey:

1. Open a new BrowsingContext.
2. Navigate to a page that's behind Basic Auth
3. Receive and network.authRequired for the navigation request with isBlocked: false.

For the next step, WebDriver BiDi does not define if the request's network.authRequired should be handled in any way. We can assume that means implementation-defined steps which is equal to ContinueWithAuthNoCredentials -> action: "default" (as this has not definition in the spec) and is one of the two probable options:

• The prompt dialog is shown to the user (how does that work with headless modes?)
• The AuthChallange is cancelled similar to network.continueWithAuth with action: "cancel"

The problem is from anyone implementing this this may create a place of friction. For example Puppeteer (historically) expects that the request will fail with 401/407 .

There are three options that come to mind:

• Should WebDriver BiDi spec auto-handle such request when network interception is not enabled? (What is a use case not to)
• Should users of WebDriver BiDi always set up interception so they can handle such cases.
• Should WebDriver BiDi spec expose a capability to how to handle this scenario.