Fix Playwright selectors for Choices.js combobox

The govuk_publishing_components v65.1.1 gem includes an upgrade of
Choices.js from v11.1.0 to v11.2.1. Choices.js v11.2.0 introduced an
ARIA accessibility fix (Choices-js/Choices#1330) that changes how
elements are exposed in the accessibility tree.

This caused Playwright's get_by_role() queries to match multiple
elements:
- get_by_role('combobox') matched both the hidden <select> and the
  visible Choices.js wrapper <div>
- get_by_role('option') matched both the hidden <option> elements
  and the visible Choices.js dropdown items

The fix uses CSS locators to target only the visible Choices.js
elements:
- div.choices[role='combobox'] for the combobox wrapper
- .choices__list--dropdown [role='option'] for dropdown options

Note: to reproduce CI failures locally, assets must be precompiled:

    rm -rf tmp/cache public/assets
    RAILS_ENV=test bundle exec rails assets:precompile
    bundle exec cucumber

Author: edavey

features/support/helpers.rb

@@ -88,10 +88,9 @@ def select_organisation(organisation)
   @organisation = organisation
   if Capybara.current_session.driver.is_a?(Capybara::Playwright::Driver)
     Capybara.current_session.driver.with_playwright_page do |page|
-      combobox = page.get_by_role("combobox", name: "Lead organisation")
+      combobox = page.locator("div.choices[role='combobox']")
       combobox.click
-      listbox = combobox.locator(".choices__list").get_by_role("listbox")
-      listbox.get_by_role("option", name: organisation.name).click
+      combobox.locator(".choices__list--dropdown [role='option']", hasText: organisation.name).click
     end
   else
     select organisation.name, from: "edition_lead_organisation_id"