"Sorry, this langauge pack doesn't exist" when attempting to set a beta language on Telegram Desktop.

[ZeroTwoOne021]

Steps to reproduce

1. open a link to set a beta language, such as https://t.me/setlanguage/ar or https://t.me/setlanguage/ja
   NOTE: this bug can be avoided by opening a link that has "-beta" at the end of it, such as https://t.me/setlanguage/ar-beta

Expected behaviour

There should be a warning saying the translation is incomplete, asking you to confirm if you want to add the language.

Actual behaviour

You get a box saying "Sorry, this language pack doesn't exist."

Operating system

Windows 11 23H2

Version of Telegram Desktop

5.8.3 x64

Installation source

Microsoft Store

Crash ID

No response

Logs

No response