JIRA Issues Macro should show issue link as part of error messages

Rendering for issue links can fail for many reasons, like for example when the remote server is down or application links are not configured correctly. In all of these cases, it would be helpful to still render a link to the issue. After all, the user viewing the page might be able to access the remote server even if the Confluence instance cannot. Also, even if the remote server is down, just knowing the issue key is often helpful.