Improve error message shown while editing a comment to the issue when jira.issue.editable is set to false

When jira.issue.editable is set to false on the workflow status, we will not able to edit the comment. The error message displayed is "We couldn’t save your comment. It might be empty or have invalid formatting. If you copy-pasted, try removing the formatting and adding it directly in the editor" which is misleading.

Improve the error message to something like "This issue is non-editable"