fix(openthread): Fix invalid host resolving for Thread end devices

Author: wqx6

components/openthread/src/esp_openthread_dns64.c

@@ -75,7 +75,9 @@ static void dns_found_handler(const char *name, const ip_addr_t *ipaddr, void *c
 {
     dns_resolve_entry_t *resolve_entry = (dns_resolve_entry_t *)callback_arg;
     if (resolve_entry && resolve_entry->found) {
-        if (ipaddr && lwip_strnicmp(name, resolve_entry->name, sizeof(resolve_entry->name)) == 0) {
+        if (!ipaddr) {
+            resolve_entry->found(name, NULL, resolve_entry->callback_arg);
+        } else if (lwip_strnicmp(name, resolve_entry->name, sizeof(resolve_entry->name)) == 0) {
             ip_addr_t ipaddr_copy = *ipaddr;
             ip6_addr_t nat64_prefix;
             if (ipaddr_copy.type == IPADDR_TYPE_V4 && esp_openthread_get_nat64_prefix(&nat64_prefix) == ESP_OK) {