[docs] Incorrect error code & reference link for docs in the example

### Type of documentation issue

Incorrect Information

### Describe the problem and the proposed solution

The example for UNAUTHORIZED error code has code and docs link as INTERNAL_SERVER_ERROR [here](https://www.unkey.com/docs/api-reference/errors/code/UNAUTHORIZED)
<img width="677" alt="test7" src="https://github.com/user-attachments/assets/0cb41b61-5f70-49dc-a56c-047dcbefa7fe">
