tests for request event and interception with redirects

[tjenkinson]

See #3993

This adds a currently failing test for intercepting a request that redirects. The interceptor is not called for the redirect.

[pavelfeldman]

The network interception in Playwright is implemented on the Browser -> Network stack boundary. Once the request is in the network stack, it is going to handle the redirects and report them, but not allow intercepting them. So while this is a limitation, it is currently considered to be 'as-designed'.

[tjenkinson]

Ah right that’s unfortunate. The test for redirects and the request event might still be useful. Happy to remove the intercept one. Also would be good to clarify this in the docs.

Is there a way of providing an allow list on urls that can be accessed (including redirects) and block the rest?

Thanks

[dgozman]

Looks good, just a minor comment in the docs.

[dgozman]

Thank you for the PR! Looks great, merging it 🚀