Add headerIsPresent assertion

Add for Cypress and Playwright.

  theHeaderContains: async ([response, headerValue, shouldContain, ...headers]) => {
    for (const header of headers) {
      if (shouldContain) {
        expect(await response.headerValue(headerValue)).toContain(header);
      } else {
        expect(await response.headerValue(headerValue)).not.toContain(header);
      }
    }
  },

h/t Petar Basic of Drunomics:
https://github.com/drunomics/playwright-drupal-starter/blob/main/tests/playwright/tests/helpers/test-methods.js