use same key as mt

pkg/services/alerting/engine.go

@@ -132,7 +132,7 @@ func (e *Engine) processJob(grafanaCtx context.Context, job *Job) error {
 		span.SetTag("alertId", evalContext.Rule.Id)
 		span.SetTag("dashboardId", evalContext.Rule.DashboardId)
 		span.SetTag("firing", evalContext.Firing)
-		span.SetTag("no_data", evalContext.NoDataFound)
+		span.SetTag("nodatapoints", evalContext.NoDataFound)
 		if evalContext.Error != nil {
 			ext.Error.Set(span, true)
 			span.LogFields(