Stats for dropped requests

### Problem Description
This is not related to a problem

### Proposed Solution
I would like to see stats for dropped requests.

### Alternatives Considered
Nothing I could think of

### Additional Information
So, when I look at the stats to see how many DNS requests have been processed by my AdGuard Home instance I don't get a full picture. This is because no stats are displayed for 'dropped' requests. These requests could be:

1) IPv6 requests dropped because the 'Disable resolving of IPv6 addresses' option is set under the 'DNS Settings'.
2) Requests from unauthorised clients (either not in the Allowed Clients list, or in the disallowed clients list)
3) Requests for unauthorised domains
4) DoT/HoH requests with an invalid/mismatched certificate

I would be useful to see the overall (if not detailed) stats for these requests which are still received and processed by AdGuard Home, but not logged (as far as I know).