Fix failing accessibility test

Remove the 'with no options set' example from being tested as part of the standard accessibility tests.

This is because the accessibility test tries to initialise the component's JS, but there is no HTML being rendered to initialise it against, returning an ElementError that Jest considers to be a test failure.

packages/govuk-frontend/src/govuk/components/service-header/accessibility.puppeteer.test.mjs

@@ -17,6 +17,10 @@ describe('/components/service-header', () => {
  it('passes accessibility tests', async () => {
  const examples = await getExamples('service-header')
 
+ // Remove the 'with no options set' example from being tested, as the
+ // component doesn't output anything in that scenario.
+ delete examples['with no options set']
+
  for (const exampleName in examples) {
  await render(page, 'service-header', examples[exampleName])
  await expect(axe(page, axeRules)).resolves.toHaveNoViolations()