Dandelion Sprout’s Nordic Filters causes the filter update to fail

### Issue Details

- **AdGuard version:**
- AdGuard Pro v4.0.4.588
- **Device model and storage size:**
- Unspecified iPhone
- **Operating system and version:**
- iOS 14.3
- **Browser or App:**
- N/A

### Reproduction
1. Install the application
2. Some time later, it will report about being unable to automatically update filters
3. Manual filter update would bring up an error message

### Expected Behavior

Filters should be automatically updated.

### Actual Behavior

Filters fail to update - both manually and automatically.

### Logs

See helpdesk ID 3051042.

### Additional Information

Problem appears sporadically, but once it appears, it does not go away.