Hi team, wrong result of timezone function

**Describe the bug**

here's sample code

```javascript
// use utc, time zone plugins
// case 1 wrong result
dayjs.tz('2025-03-24T11:00:00', 'Asia/Seoul').utcOffset(8).format()
// => '2025-03-24T09:00:00+08:00'
// case 2 correct result
dayjs(dayjs.tz('2025-03-24T11:00:00', 'Asia/Seoul').format()).utcOffset(8).format()
// => '2025-03-24T10:00:00+08:00'
```

**Information**
- Day.js Version: 1.1.13
- OS: macOS
- Browser : Chrome 134
- Time zone: Asia/Shanghai

Start by running the two JavaScript examples from the issue with the UTC and timezone plugins enabled, using Asia/Seoul and the requested UTC offset. Compare the differing formatted results and trace the timezone and utcOffset handling. Done means the equivalent calls produce the expected consistent time and offset.

Written by the indexing model from the issue text.