Support beforeInitialisation() options, multiple modules

[colinrotherham]

This PR is split out from #4266 and includes:

1. Support custom beforeInitialisation() browser options
2. Support multiple $modules being initialised in renderAndInitialise()

This follows a "Custom Puppeteer browser options" discussion on Slack and first suggested by @romaricpascal

Custom initialisation example

Render a single button but clone it before both are initialised together

const examples = await getExamples('button')

// Render single button
renderAndInitialise(page, 'button', {
  params: examples.default,

  // Duplicate button before initialisation
  beforeInitialisation($module, { className }) {
    const $button1 = $module
    
    // Create 2nd button
    const $button2 = el.cloneNode(true)

    // Append 2nd button, configure
    $button1.parentNode.appendChild($button2)
    $button2.setAttribute('class', className)
  },
  
  // Pass custom options to browser
  beforeInitialisationOptions: {
    className: 'govuk-button--dodgy'
  }
})

[github-actions]

📋 Stats

File sizes

File	Size
dist/govuk-frontend-4.6.0.min.css	118.07 KiB
dist/govuk-frontend-4.6.0.min.js	47.1 KiB
dist/govuk-frontend-ie8-4.6.0.min.css	79.27 KiB
packages/govuk-frontend/dist/govuk/all.bundle.js	75.42 KiB
packages/govuk-frontend/dist/govuk/all.bundle.mjs	70.83 KiB
packages/govuk-frontend/dist/govuk/all.mjs	3.84 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend-component.mjs	359 B
packages/govuk-frontend/dist/govuk/govuk-frontend.min.css	113.99 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend.min.js	36.73 KiB
packages/govuk-frontend/dist/govuk/i18n.mjs	5.3 KiB

Modules

File	Size
all.mjs	67.15 KiB
components/accordion/accordion.mjs	20.61 KiB
components/button/button.mjs	4.55 KiB
components/character-count/character-count.mjs	20.73 KiB
components/checkboxes/checkboxes.mjs	5.69 KiB
components/error-summary/error-summary.mjs	5.85 KiB
components/exit-this-page/exit-this-page.mjs	15.49 KiB
components/header/header.mjs	3.84 KiB
components/notification-banner/notification-banner.mjs	4.39 KiB
components/radios/radios.mjs	4.68 KiB
components/skip-link/skip-link.mjs	3.73 KiB
components/tabs/tabs.mjs	9.41 KiB

View stats and visualisations on the review app

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Action run for e9842b7

[domoscargin]

Is this semi-colon doing something fancy?

[colinrotherham]

Yeah caught me out too

It's a Prettier protection against those parentheses () becoming a function call
https://prettier.io/docs/en/rationale#semicolons

ESLint does it too but not nearly as much

[domoscargin]

Ah, fair enough.

[domoscargin]

I really like this, enables a lot more shenanigans before we actually run the test, and lays the ground for removing the Review app from tests in the future if we want to.

One tiny comment which I think is either a typo or is doing something I don't understand, but otherwise hot to trot.