Unable to do English B1 test in Android Platform

### Describe the Issue

Lessons and quizzes of the content are usable. Only the final test seemed to fail to display properly.

### Affected Page

This is mobile / android platform, no link to provide. See the screenshot for better instruction.

### Your code

This is the only message I saw when the error happened:

```txt
Unknown Challenge, info : 30
```

### Expected behavior

I should be able to do the test and earn certification.

### Screenshots

Screenshot that explain how I caught the error:

### System

- Device: android
- OS: Android 14
- Browser: android application from play store
- Version: 7.5.6

### Additional context

In the case this was a design, feature is not ready for instance, kindly put out a friendly message. Hide away the button to the test would be an option too. It will be more professional than let everyone see an error code. Very confused.

If this is an under working feature, may I know where I can follow to the discussion about it? If my suspection is correct, it should be stuck around anti-cheating right?

Start by reproducing the English B1 final test on Android 14 with app version 7.5.6, then trace the source of the “Unknown Challenge, info : 30” message. Done means the final test displays and can be completed for certification, or the unavailable feature shows a friendly message instead of the error.

Written by the indexing model from the issue text.