fix 员工支持客服身份

cooleshow-user/user-biz/src/main/java/com/yonge/cooleshow/biz/dal/service/impl/TeacherServiceImpl.java

@@ -735,7 +735,7 @@ public class TeacherServiceImpl extends ServiceImpl<TeacherDao, Teacher> impleme
         // 重置学生关联客服绑定
         studentService.update(null, new UpdateWrapper<Student>().lambda()
                 .eq(Student::getImCustomerId, imCustomerServiceId)
-                .set(Student::getImCustomerId, imCustomerServiceId)
+                .set(Student::getImCustomerId, "")
                 .set(Student::getCustomerId, null));
     }