Exporting an Assets Report which references a deleted Jira user will fail as CSV or JSON

Issue Summary

This is reproducible on Data Center: YES

Steps to Reproduce

1. Create an Assets ObjectType which contains a Jira User attribute and set Minimum Cardinality to '1'
2. Create Objects referencing Jira Users and then delete at least one user from Jira
3. Notice the Object will show 'Unknown' for the user attribute
4. Create a Filter to show this ObjectType and include the User attribute in the columns
5. Create a Report on the above filter and confirm User column shown
6. Attempt to export the Report as CSV or JSON format

Note: export as XML provides correct output

Expected Results

Expect report exported with 'blank' entry for the Object with user Attribute which shows as 'Unknown' as the displayed Report output.

Actual Results

No output is generated and no UI error or popup. You have to check the browser console for the error which depending on browser type may show

Uncaught TypeError: e is null

or

Uncaught TypeError: Cannot read properties of null (reading 'label')

Workaround

By setting the 'Minimum Cardinality' of the Jira User Attribute to '0' allows the CSV/JSON export to complete.