Mark OpenQA job as failed on "unkown status"

A GitHub-OpenQA job failed with "unknown status" [1] and yet, it had
marked the respective OpenQA tests as green/passing. This was because
in the "unkown status" condition it was not explicitly setting a failing
check for the respective OpenQA job on GitHub.

[1]: https://github.com/freedomofpress/securedrop-workstation/actions/runs/19579932625/job/56075156340?pr=1373#step:7:90

Author: deeplow

.github/workflows/openqa.yml

@@ -112,6 +112,7 @@ jobs:
                 *)
                     echo "Unknown test status: $openqa_result"
                     workflow_exit_status=1
+                    github_state="error"
                     ;;
             esac
             curl --fail -L -X POST \