Using GET for a Test Run Comment is not working when the Comment is empty

Description
Using GET for a Test Run Comment is not working when the Comment is empty.

Pre-conditions
Execution without any comment:

How to reproduce

1. perform the request, using REST API either v1 or v2:

   http://SERVER/rest/raven/1.0/api/testrun/1602/comment
   
   http://SERVER/rest/raven/2.0/api/testrun/1602/comment
   

Actual result/Attachments
Null result in both requests:

Expected result
Empty string.

Version

• Xray v6.1.3