Pull request: imp-json-resp

Merge in DNS/adguard-home from imp-json-resp to master

Squashed commit of the following:

commit 44532b6fa551815e5ea876e7320ce0a73c32b6fb
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Sep 30 15:59:58 2022 +0300

    all: imp json resp

internal/dhcpd/http_unix.go

@@ -78,18 +78,7 @@ func (s *server) handleDHCPStatus(w http.ResponseWriter, r *http.Request) {
 	status.Leases = s.Leases(LeasesDynamic)
 	status.StaticLeases = s.Leases(LeasesStatic)
 
-	w.Header().Set("Content-Type", "application/json")
-
-	err := json.NewEncoder(w).Encode(status)
-	if err != nil {
-		aghhttp.Error(
-			r,
-			w,
-			http.StatusInternalServerError,
-			"Unable to marshal DHCP status json: %s",
-			err,
-		)
-	}
+	_ = aghhttp.WriteJSONResponse(w, r, status)
 }
 
 func (s *server) enableDHCP(ifaceName string) (code int, err error) {