When trying to post a comment consisting of only inline comments to an audit, we get a fatal: `Call to a member function getAction() on a non-object`.
Traces from the log:
```lang=text
PHP Warning: Uncaught exception 'RuntimeException' with message 'Undefined variable: comment' in /***/libphutil/src/error/PhutilErrorHandler.php:210
Stack trace:
#0 /***/phabricator/src/applications/audit/editor/PhabricatorAuditCommentEditor.php(77): PhutilErrorHandler::handleError(8, 'Undefined varia...', '/***/p...', 77, Array)
#1 /***/phabricator/src/applications/audit/controller/PhabricatorAuditAddCommentController.php(66): PhabricatorAuditCommentEditor->addComments(Array)
#2 /***/phabricator/webroot/index.php(95): PhabricatorAuditAddCommentController->processRequest()
#3 {main}
thrown in /***/libphutil/src/error/PhutilErrorHandler.php on line 210
PHP Fatal error: Call to a member function getAction() on a non-object in /***/phabricator/src/applications/audit/editor/PhabricatorAuditCommentEditor.php on line 77
```
Note: when adding regular comment text, it //does// work.