优化程序初始化逻辑，修复无网络的情况下的初始化问题

src/renderer/views/list/List.vue

@@ -52,7 +52,7 @@ export default {
     const scrollIndex = to.query.scrollIndex
     const isAnimation = from.query.id == to.query.id
     this.$nextTick(() => {
-      this.$refs.musicList.restoreScroll(scrollIndex, isAnimation)
+      this.$refs.musicList?.restoreScroll(scrollIndex, isAnimation)
     })
     return {
       path: '/list',
@@ -60,7 +60,7 @@ export default {
     }
   },
   beforeRouteLeave(to, from) {
-    this.$refs.musicList.saveListPosition()
+    this.$refs.musicList?.saveListPosition()
   },
   created() {
     this.listId = this.$route.query.id