browser: add page.on('requestfailed') event handler

[pkalsi97]

What?

This PR Adds the page.on('requestfailed') event handler to the k6 browser module, following the Playwright API.

This event fires when a network request fails to reach the server:
in the following cases : DNS errors, connection refused, timeouts, etc.
It does not fire for HTTP 4xx/5xx responses, which are successful network requests.

Note: I have closely followed the implementation of page.on('request') and page.on('response') events.

Why?

Reasons mentioned in the issue #4299 description.

Checklist

• I have performed a self-review of my code.
• I have commented on my code, particularly in hard-to-understand areas.
• I have added tests for my changes.
• I have run linter and tests locally (make check) and all pass.

Checklist: Documentation (only for k6 maintainers and if relevant)

Please do not merge this PR until the following items are filled out.

• I have added the correct milestone and labels to the PR.
• I have updated the release notes: link
• I have updated or added an issue to the k6-documentation: grafana/k6-docs#NUMBER if applicable
• I have updated or added an issue to the TypeScript definitions: grafana/k6-DefinitelyTyped#NUMBER if applicable

Related PR(s)/Issue(s)

Closes: #4299
Parent: #4232

[mstoykov]

Thank you for the PR, and sorry for the slow reviews - the holidays and catching up has been getting in the way.

Over all looks really good, my only concern is the skipping of the test in the middle. I really do not want this to be happening, either we know that this hsouldn't work in some cases and we skip early or we are running the test. This test currently will practically never fail - it will just be skipped. Which isn't good for tests.

[pkalsi97]

@mstoykov Thanks a lot for taking a look at it, i hope you had a great holiday.

I have updated the test to follow a more deterministic approach where:

1. page.Route() with route.Abort() is used to intercept and fail requests at the browser level, instead of relying on external network behavior.
2. Removes the conditional t.Skip(), test will now fail if no requestfailed events are captured

[mstoykov]

LGTM now

[ankur22]

Awesome! Thanks for this 🚀

[ankur22]

@pkalsi97 I've merged in your other PR (#5486) and now we're seeing two things that need some attention:

1. lint issue
2. Merge conflict

Could you please take a look at these two and resolve them?

[pkalsi97]

@ankur22 Thanks i have addressed the lint issue and resolved the conflict. :)