Review the redirect mode, analytics, and promotional messaging functionality

Found a bug with the "monthly_payment_on_add_to_cart" setting, the product has a "default" view mode but not a "full" one. So, the "monthly_payment" form element was never displayed.
Opened MR with the fixes.

Also, in src/Plugin/Field/FieldFormatter/AffirmFormatter.php there was a condition:

      if ($item->currency_code !== 'USD') {
        $elements[$delta] = [];
      }

I tested this formatter with CA and USD, and everything works fine, so I removed this condition.

Committed!

Ah, good find re: the monthly estimate not appearing. I was actually wondering about that during my testing but forgot to note it. : )