Fix a non-deterministic webhook test (#7952)

`test_two_project_webhooks_intersection` is supposed to trigger each
webhook once. However, the first one of these webhooks actually gets
triggered twice, because creating a task causes the project's
`updated_date` to be bumped, which triggers an `update:project` event.

The test still passes a lot of the time (I guess because the second
delivery doesn't appear immediately?), but sometimes it fails. It's very
easy to make it fail consistently, though - just add a `sleep(5)` before
the `get_deliveries` calls.

Fix this by changing the first webhook's second event to something that
will not be triggered.

tests/python/rest_api/test_webhooks_sender.py

@@ -208,7 +208,7 @@ def test_two_project_webhooks_intersection(self):
         assert response.status_code == HTTPStatus.CREATED
 
         project_id = response.json()["id"]
-        events_1 = ["create:task", "update:project"]
+        events_1 = ["create:task", "update:issue"]
         events_2 = ["create:task", "create:issue"]
         webhook_id_1 = create_webhook(events_1, "project", project_id=project_id)["id"]
         webhook_id_2 = create_webhook(events_2, "project", project_id=project_id)["id"]