POST /system/jira-test bundled 4 independent checks (enabled, url,
admin_email, admin_api_token) behind has_admin_jira_configured() but
always blamed "Admin Email and Admin API Token" regardless of which one
failed. Found via live QA: URL/email/token were all correctly saved, but
the "Enable Jira Integration" toggle was never switched on — the error
message pointed at the wrong fields, making it look like the already-set
credentials were missing.