update: 优化nvue下获取context时填错id报错不准确的问题

src/platforms/app-plus-nvue/service/api/util.js

@@ -57,7 +57,7 @@ function findRefByElm (id, elm) {
   if (!id || !elm) {
     return
   }
-  if (elm.attr.id === id) {
+  if (elm.attr && elm.attr.id === id) {
     return elm
   }
   const children = elm.children