Issue Summary

Error 500 on Get Pages request in Confluence Cloud API whenever you request the contributors and an anonymous edit has been made to the page.

Steps to Reproduce

1. Make an edit to a public page anonymously

1. Then, make the following REST call.
    
    curl --location "https://${sitename}.atlassian.net/wiki/api/v2/pages/${page_id}?include-collaborators=true" --user $EMAIL:$TOKEN

In splunk we see the following error.
 {{Cannot invoke "com.atlassian.confluence.user.ConfluenceUser.getAccountIdAsString()" because "this.confluenceUser" is null; }}

Splunk Query

 
 `micros_confluence-prod-ap-5` "16c33e5d-60d9-4922-8211-71a3f248552e" d0fb00cf7c9a48f68da450f354250221

Expected Results

It's expected that the request returns at least informing that an anonymous contributor has edited the page instead of an error.

Actual Results

We get Error 500: "status":500,"code":"INTERNAL_SERVER_ERROR","title":"Internal Server Error","detail":null

Workaround

There's no current workaround.