Option to advertise the same DNS IP multiple times in DHCP response

### 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 have a very strict blacklist-everything-by-default configuration for my Android TV:

```
# Blacklist everything
||*.*^$client='tv'

# Allow basic YT support
@@||youtube.com^$client='tv'
@@||googlevideo.com^$client='tv'
@@i.ytimg.com^$client='tv'
@@yt3.ggpht.com^$client='tv'
```

It was working fine for some time but suddenly stopped working. The TV is also unable to resolve local services on my LAN.

The TV periodically tries to contact Adguard Home's DNS but gets most of its requests denied:


My assumption is that Android ends up believing Adguard Home's DNS is not working and falls back to using Google's DNS.

Here's the network configuration of my TV:



(Sorry for the disgusting pics)

As you can see, the second DNS field shows `0.0.0.0`, it's most likely the reason why Android believes it's ok to fallback to some other DNS.

### Proposed solution

I believe that advertising the same DNS address multiple times would resolve this issue. PiHole is already doing that:


Related PiHole issue: https://github.com/pi-hole/pi-hole/pull/3846

### Alternatives considered and additional information

Using a static network configuration. I'd like to avoid that, I might buy another TV at some point, I don't want to rely on client configuration.