Add 'questOwner' to the return data of a 'questActivity' webhook. (#13277)

* Update webhook.js

Add `questOwner: group.quest.leader,` to webhook.js

* Update POST-groups_groupId_quests_invite.test.js

Test if questOwner contains the correct data

* Update POST-groups_groupId_quests_invite.test.js

* Update webhooks.test.js

test/api/unit/libs/webhooks.test.js

@@ -656,9 +656,11 @@ describe('webhooks', () => {
           id: 'group-id',
           name: 'some group',
           otherData: 'foo',
+          quest: {},
         },
         quest: {
           key: 'some-key',
+          questOwner: 'user-id',
         },
       };
     });