DNS leak detected on ippure.com when DNS-over-* server is selected

### Please answer the following questions for yourself before submitting an issue

- [x] Filters were updated before reproducing an issue
- [x] I checked the [knowledge base](https://adguard.com/kb/) and found no answer
- [x] I checked to make sure that this issue has not already been filed

### AdGuard version

8.0.0 RC 4 (5553)

### Browser version

Google Chrome 151.0.7922.72

### OS version

Windows 11 25H2

### Traffic filtering

- [x] yes, I do

### Ad Blocking

_No response_

### Privacy

_No response_

### Social

_No response_

### Annoyances

_No response_

### Security

_No response_

### Other

_No response_

### Language-specific

_No response_

### Which DNS server do you use?

Cloudflare DNS

### DNS protocol

DNS-over-HTTPS

### Custom DNS

_No response_

### What Stealth Mode options do you have enabled?

_No response_

### Support ticket ID

_No response_

### Issue Details

Steps to reproduce:
1.Select any DNS with DNS-over-*.
2.Open a website like ippure.com for testing DNS.
3.

### Expected Behavior

The test result is the DNS selected in AdGuard.

### Actual Behavior

DNS leak, the DNS-over-* feature in AdGuard software is malfunctioning.

### Screenshots

### Additional Information

_No response_