feat(k6/browser): support or() locator

[amontfaucon]

What?

Add support for or() in locators.

Why?

This is a feature supported in playwright and hinders reusability of scripts with k6. It is very useful in improving test stability (e.g. handle login screens, MFA prompt, cookie consent that may not trigger systematically).

Implementation is inspired from the one of playwright. Only or() was added for now to keep it simple since and() is easier to achieve through other means.

For example, with this PR one can do the following:

import { browser } from "k6/browser";
import { expect } from 'https://jslib.k6.io/k6-testing/0.6.1/index.js';

export const options = {
    scenarios: {
        browse: {
            executor: "shared-iterations",
            iterations: 1,
            options: {
                browser: {
                    type: "chromium",
                },
            },
        },
    }
};

export default async function () {
    const page = await browser.newPage();

    const orSelector = page.locator("#using-k6-browser").or(page.locator("#using-k6"));

    await page.goto("https://grafana.com/docs/k6/latest/using-k6/");

    await expect(orSelector).toHaveText("Using k6");
    await expect(orSelector).not.toHaveText("Using k6 browser");
    await expect(orSelector).toHaveAttribute("id", "using-k6")

    await page.goto("https://grafana.com/docs/k6/latest/using-k6-browser/");

    await expect(orSelector).toHaveText("Using k6 browser");
    await expect(orSelector).not.toHaveText("Using k6");
    await expect(orSelector).toHaveAttribute("id", "using-k6-browser")
}

Note: this will require a change in the TS types definitions.

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)

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