We use string arguments in all other places, so these two places are a
bit inconsistent in that sense. Moreover, it's just one argument now,
which makes it a bit easier to read and see what it does because we
don't have to pass the always-empty options argument anymore. Finally,
doing it like this ensures it works in all Puppeteer versions given
https://github.com/puppeteer/puppeteer/issues/7836.