User can save empty comments from GH, though they don't get save in JIRA issue

Steps:
1. Goto planning board and double click on any issue to view it in detail view.
2. From drop down menu select comment.
3. Click "Update" without entering any comment.

Result:
1. It proceed without any error message though the best part is no comment is saved for issue.

Expected:
1. User should get a proper warning message, blank comments can't be saved or we can disable update button till user enter some text.