refactor: 调整推荐题目api调用顺序

src/views/quiz/DoRecommendQuestion.vue

@@ -86,6 +86,8 @@ export default {
         this.knowledgeTree = constructTree(res)
       })
       .catch(err => this.$setErrorMessage(err.response.data.msg))
+  },
+  mounted () {
     this.getQuestions()
   },
   methods: {