fix(测试跟踪): 功能用例导出弹窗关闭

--bug=1023775 --user=宋昌昌 【测试跟踪】用例导出，点击导出，弹窗没有自动关闭 https://www.tapd.cn/55049933/s/1342757

test-track/frontend/src/business/case/components/export/TestCaseExportToExcel.vue

@@ -64,8 +64,9 @@ export default {
       if (this.$refs.testCaseExportFieldSelectTable) {
         param = this.$refs.testCaseExportFieldSelectTable.getExportParam();
       }
-      param.exportAll = this.exportAll
+      param.exportAll = this.exportAll;
       this.$emit('exportTestCase', this.exportType, param);
+      this.close();
     }
   }
 }