fix: resultdump: Check that the error has a circuit
Because if the error is not a circuit error, it does not have that attribute.
GitLab is used only for code review, issue tracking and project management. Canonical locations for source code are still https://gitweb.torproject.org/ https://git.torproject.org/ and git-rw.torproject.org.
Because if the error is not a circuit error, it does not have that attribute.