[client] Normalize DNS record names to lowercase in local handler update (#3323)

* [client] Normalize DNS record names to lowercase in lookup

client/internal/dns/server.go

@@ -454,6 +454,7 @@ func (s *DefaultServer) buildLocalHandlerUpdate(customZones []nbdns.CustomZone)
 			if record.Class != nbdns.DefaultClass {
 				return nil, nil, fmt.Errorf("received an invalid class type: %s", record.Class)
 			}
+
 			key := buildRecordKey(record.Name, class, uint16(record.Type))
 			localRecords[key] = record
 		}