'message' property is never populated on ActivityMessageNotification queries

[ben-hig]

When querying for ActivityMessageNotifications (or any other notification type that includes a message property), the message is always null.

Things considered:

• Issue occurs for both private and public messages
• Issue occurs for messages which have not been deleted
• Issue occurs for queries that are both paginated and for a specific ActivitMessageNotification

Show example SOQL query

{
  Page (page: 1) {
    pageInfo {
        lastPage
    }
    notifications(type: ACTIVITY_MESSAGE) {
      ...on ActivityMessageNotification {
        id
        activityId
        createdAt
        message {
          id
        }
      }
    }
  }
}

Show results of example SOQL query

{
  "Page": {
    "pageInfo": {
      "lastPage": 1
    },
    "notifications": [
      {
        "id": 293189482,
        "activityId": 383742138,
        "createdAt": 1650890396,
        "message": null
      },
      {
        "id": 74677190,
        "activityId": 100506986,
        "createdAt": 1595206559,
        "message": null
      }
    ]
  }
}