fix lint error

src/features/OnlineExam/Examing/ExamingHome.vue

@@ -562,7 +562,6 @@ export default {
         const res = await this.$http.get(
           "/api/ecs_oe_student/examControl/endExam"
         );
-        let resAfter;
         if (res.status === 200) {
           this.$router.replace({
             path: `/online-exam/exam/${examId}/examRecordData/${examRecordDataId}/end`,