function onRequest(request) {
      if (request.url().includes('https://www.googleapis.com')) {
        interceptedRequest = request;
        request.respond(psiResponse);
      } else {
        request.continue();
      }
    }
Sniffs just the request made to the PSI API. All other requests
fall through.
To set the mocked PSI response, assign `psiResponse`.
To read the intercepted request, use `interceptedRequest`.
@param {import('puppeteer').HTTPRequest} request