Option to disable caсhing of SERVFAIL responses

### Prerequisites

- [X] I have checked the [Wiki](https://github.com/AdguardTeam/AdGuardHome/wiki) and [Discussions](https://github.com/AdguardTeam/AdGuardHome/discussions) and found no answer

- [X] I have searched other issues and found no duplicates

- [X] I want to request a feature or enhancement and not ask a question

### The problem

I would like to be able to disable the cahing of SERVFAIL responses by adguard.

### Proposed solution

A configuration option to disable the caching of SERVFAIL requests and/or treat it as a failure

### Alternatives considered and additional information

It has been stated in https://github.com/AdguardTeam/AdGuardHome/issues/5924 that this is intended behavior, but the spec does not require the server to do this. So I'm asking for the ability to disable it.

Related: https://github.com/AdguardTeam/AdGuardHome/issues/7292