feat: restructure events payload (#8143)

* refactor: restructure events payload

Breaking change: This PR changes the event payload accepted by the event
listeners

* refactor: fix failing tests and implement feedback

* add integration tests

* fix timeout

---------

Co-authored-by: Adrien de Peretti <adrien.deperetti@gmail.com>

packages/modules/fulfillment/integration-tests/__fixtures__/events.ts

@@ -9,7 +9,7 @@ export function buildExpectedEventMessageShape(options: {
   options?: Record<string, unknown>
 }): EventBusTypes.Message {
   return {
-    eventName: options.eventName,
+    name: options.eventName,
     metadata: {
       action: options.action,
       eventGroupId: options.eventGroupId,