title: Stripe checkout: Pass metadata on Session object creation and receive it in checkout.session.completed event
body: <p>I'm implementing Stripe checkout on a website and I want to pass some specific data on checkout.session.complete.
  Here is what I tried: </p>
  
  <pre><code>'mode' =&gt; 'payment',
  'payment_intent_data' =&gt; [
      'metadata' =&gt; [
          'eventId' =&gt; $eventId,
      ],
   ],
  </code></pre>
  
  <p>But I don't receive those datas in my webhook. What am I doing wrong ?</p>