Wrong language setting after installation

[handsome_feng]

OS: Ubuntu Kylin 24.04 daily 20240420

Steps to reproduction:

1. Choose Chinese when installing
2. reboot after installation
3. login and get the outputs of locale:
```
LANG=zh_CN.UTF-8
LANGUAGE=en
LC_CTYPE="zh_CN.UTF-8"
LC_NUMERIC="zh_CN.UTF-8"
LC_TIME="zh_CN.UTF-8"
LC_COLLATE="zh_CN.UTF-8"
LC_MONETARY="zh_CN.UTF-8"
LC_MESSAGES="zh_CN.UTF-8"
LC_PAPER="zh_CN.UTF-8"
LC_NAME="zh_CN.UTF-8"
LC_ADDRESS="zh_CN.UTF-8"
LC_TELEPHONE="zh_CN.UTF-8"
LC_MEASUREMENT="zh_CN.UTF-8"
LC_IDENTIFICATION="zh_CN.UTF-8"
LC_ALL=
```

LANGUAGE is set to en which is wrong.

[handsome_feng (feng-kylin)]

Additionally:

The value of LANGUAGE is restored to the correct value after one reboot, i.e. the wrong value appears only on the first boot after installation.

and the outputs of locale after reboot again:
```
LANG=zh_CN.UTF-8
LANGUAGE=zh_CN
LC_CTYPE="zh_CN.UTF-8"
LC_NUMERIC="zh_CN.UTF-8"
LC_TIME="zh_CN.UTF-8"
LC_COLLATE="zh_CN.UTF-8"
LC_MONETARY="zh_CN.UTF-8"
LC_MESSAGES="zh_CN.UTF-8"
LC_PAPER="zh_CN.UTF-8"
LC_NAME="zh_CN.UTF-8"
LC_ADDRESS="zh_CN.UTF-8"
LC_TELEPHONE="zh_CN.UTF-8"
LC_MEASUREMENT="zh_CN.UTF-8"
LC_IDENTIFICATION="zh_CN.UTF-8"
LC_ALL=
```

[fossfreedom (fossfreedom)]

Similar LANGUAGE observation here https://bugs.launchpad.net/ubuntu-desktop-provision/+bug/2063026

However, rebooting didnt change to the expected chosen LANGUAGE in ubuntu-desktop-provision

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/2063037

[handsome_feng (feng-kylin)]

Hello, Is there any progress?

[Sebastien Bacher (seb128)]

@handsome_feng, no, or there would be some update on the bug. The release has been exhausting and several people have been taking time off work after it.