超过断点次数，提示优化

src/features/Login/Login.vue

@@ -359,7 +359,7 @@ export default {
             content: `超出最大断点续考次数(${
               examingRes.maxInterruptNum
             })，正在自动交卷...`,
-            duration: 30,
+            duration: 15,
             closable: true
           });
           this.$Spin.show({
@@ -375,7 +375,6 @@ export default {
           const res = await this.$http.get(
             "/api/ecs_oe_student/examControl/endExam"
           );
-          this.$Message.destroy();
           if (res.status === 200) {
             this.$router.replace({
               path: `/online-exam/exam/${examingRes.examId}/examRecordData/${