[BUG] Setting Language zh-CN unsuccessful

[Rebuilding127]

Environment

Self-Hosted (Docker)

System

Docker 27.2.1

Version

3.1.1

Describe the problem

Set the language zh or zh-CN in user custom config.yml, then rebuild service or restart docker, it is unsuccessful.
The chroem devtools console warning : Unsupported Language: 'zh-CN', and the config panel shows language is "🇬🇧 English".

Additional info

No response

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[Rebuilding127]

It works when I set the language cn in config.yml.
But the devtools console warning message Error applying language, it's config may be missing of incomplete when I open the language setting panel in config UI.