[BUG] 自定义LocalDateTime Reader无效

### 问题描述
*简要描述您碰到的问题。*

### 环境信息
*请填写以下信息：*

- OS信息： MacBook M1 Pro
- JDK信息： 1.8.0_312
- 版本信息：2.0.44

### 重现步骤
JSON.register(LocalDateTime.class, new LocalDateTimeReader(new SmartDateFormat())); // SmartDateFormat自己随便定一个，能识别多种格式就行

@Data
public class Person {
private Integer age = 10;
private Sex sex = Sex.F;

@JSONField(format = "yyyyMMddHHmmss")
private LocalDateTime localDateTime = LocalDateTime.now();

private LocalDate localDate = LocalDate.now();
private LocalTime localTime = LocalTime.now();
private DateTime dateTime = new DateTime();

private Integer count;
}

## main
val person1 = new Person();
val str1 = JSON.toJSONString(person1);
val p = JSON.parseObject(str1,Person.class); // 这里报错，报错堆栈可以看到并未使用自定义的SmartDateFormat来解析日期数据

Reproduce the case starting with JSON.register, LocalDateTimeReader, the @JSONField(format = "yyyyMMddHHmmss") field, and JSON.parseObject. Trace the deserialization path and verify that the registered SmartDateFormat-based reader is used for LocalDateTime; the issue is done when the example parses successfully with the custom reader.

Written by the indexing model from the issue text.