feat(wd): screenshots for sessions

[kobenguyent]

Motivation/Description of the PR

• WD Helper: Currently only screenshot of the active session is saved, this PR aims to save the screenshot of every session for easy debugging

Scenario('should save screenshot for sessions @WebDriverIO @Puppeteer @Playwright', async ({ I }) => {
  await I.amOnPage('/form/bug1467');
  await I.saveScreenshot('original.png');
  await I.amOnPage('/');
  await I.saveScreenshot('main_session.png');
  session('john', async () => {
    await I.amOnPage('/form/bug1467');
    event.dispatcher.emit(event.test.failed, this);
  });

  const fileName = clearString('should save screenshot for active session @WebDriverIO @Puppeteer @Playwright');
  const [original, failed] = await I.getSHA256Digests([
    `${output_dir}/original.png`,
    `${output_dir}/john_${fileName}.failed.png`,
  ]);

  // Assert that screenshots of same page in same session are equal
  await I.expectEqual(original, failed);

  // Assert that screenshots of sessions are created
  const [main_original, session_failed] = await I.getSHA256Digests([
    `${output_dir}/main_session.png`,
    `${output_dir}/john_${fileName}.failed.png`,
  ]);
  await I.expectNotEqual(main_original, session_failed);
});

Applicable helpers:

• WebDriver

Applicable plugins:

• screenshotOnFail

Type of change

• 🚀 New functionality

Checklist:

• Tests have been added
• Documentation has been added (Run npm run docs)
• Lint checking (Run npm run lint)
• Local tests are passed (Run npm test)