fix workflow controller make panic due to processedTmpl is nil

Signed-off-by: chengjoey <30427474+chengjoey@users.noreply.github.com>

workflow/controller/dag.go

@@ -449,7 +449,7 @@ func (woc *wfOperationCtx) executeDAGTask(ctx context.Context, dagCtx *dagContex
 		}
 
 		// Release acquired lock completed task.
-		if tmpl != nil {
+		if processedTmpl != nil {
 			woc.controller.syncManager.Release(woc.wf, node.ID, processedTmpl.Synchronization)
 		}