Add function `Cookies.enabled(): bool` that returns if cookie access is enabled

Is your feature request related to a problem? Please describe. Cookies are disabled when a page is in a sandboxed iframe. In this case, trying to access document.cookie throws an error:

SecurityError: Document.cookie getter: Forbidden in a sandboxed document without the 'allow-same-origin' flag.

Describe the solution you'd like It would be helpful to have a function from the Cookies library to check.

Describe alternatives you've considered I've implemented my own:

function cookies_enabled() {
  try {
    // In security locked iframes, document.cookie throws an error.
    document.cookie;
    return true;
  } catch (e) {
    return false;
  }
}

Additional context Add any other context or screenshots about the feature request here.