Issue Summary

When using the v2 Page Rest API, if we use the include-collaborators query param and the page was modified by an anon user, an error gets thrown and also the JSON response is invalid due to the error payload.

Steps to Reproduce

1. Create a page.
2. Allow anonymous access for your tenant and your space, so anonymous users can edit pages.
3. Edit the page using as an anonymous user.
4. Run /wiki/api/v2/pages/{page-id}?include-collaborators=true  request in Postman for the edited page.

Expected Results

No errors, and a valid JSON

Actual Results

{
    "parentId": "ABC",
    "spaceId": "ABC",
    "ownerId": "ABC",
    "lastOwnerId": null,
    "authorId": "ABC",
    "collaborators": [
        {}
    ]
}{
    "errors": [
        {
            "status": 500,
            "code": "INTERNAL_SERVER_ERROR",
            "title": "Internal Server Error",
            "detail": null
        }
    ]
} 

Workaround

The current work around is to not use the include-collaborators query param if this error is seen.