Don't unblock interception if last interception is removed

[Lightning00Blade]

WebDriver BiDi requires that a request continues to be blocked even if you remove all it's interceptions are removed.
In CDP if the Fetch.disable is called successfully, all the request that were blocked will be continued with out any overrides.
This means we have to either workaround this issue Prototype: #2135

The problem is that this introduces certain problems when we leave the request hanging (block then never continue).
The main issue seems to be with AuthRequired events as that blocks any further navigation until resolved.
Trying to navigate to a different page seems to work as the (blocked) request is aborted by the render.

Also another problem is we can't disable the Network domain while there is a blocked request.

Chromium inspector-protocol navigation test: https://chromium-review.googlesource.com/c/chromium/src/+/5463590 (seems to work with content-shell)
Chromium browser_tests: https://chromium-review.googlesource.com/c/chromium/src/+/5472256
Chromium inspector-protocol disable Network test: https://chromium-review.googlesource.com/c/chromium/src/+/5465648