fix: node type metas comment node add "comment" for key (#2325)

Author: zhuangjie1125

backend/domain/workflow/entity/node_meta.go

@@ -604,7 +604,7 @@ var NodeTypeMetas = map[NodeType]*NodeTypeMeta{
 	},
 	NodeTypeComment: {
 		ID:           31,
-		Key:          "",
+		Key:          NodeTypeComment,
 		Name:         "注释",
 		Category:     "",             // Not found in cate_list
 		Desc:         "comment_desc", // Placeholder from JSON