Setting UTC offset near start of daylight savings alters the time

**Describe the bug**
Adding a UTC offset to a date near the beginning of daylight savings changes the time.

Note: in time zone Europe/London, daylight savings starts on 2023-03-26 at 01:00 GMT.

Example:
> dayjs('2023-03-25T00:00:00+00:00').utc().utcOffset(1)
// '2023-03-25T01:00:00+01:00' The same as the original time.

> dayjs('2023-03-26T00:00:00+00:00').utc().utcOffset(1)
// '2023-03-26T02:00:00+01:00' This is one hour ahead of the original time.

> dayjs('2023-03-27T00:00:00+00:00').utc().utcOffset(1)
// '2023-03-27T01:00:00+01:00' The same as the original time.

**Expected behavior**
Changing the UTC offset should not change the time.

**Information**
- Day.js Version 1.11.7
- OS: macOS Ventura 13.2
- Node version: v17.7.0
- Time zone: GMT

Start by reproducing the three UTC and utcOffset examples from the issue, focusing on the UTC-offset handling around the Europe/London daylight-saving transition. Verify that applying the offset preserves the original instant and add coverage for the dates before, during, and after the transition.

Written by the indexing model from the issue text.