TF-2271 Implement dns lookup to get jmap url

Signed-off-by: dab246 <tdvu@linagora.com>
(cherry picked from commit 7b0c0015a15a243b6b4aef3d78e7653d556ad109)

lib/features/login/data/network/dns_service.dart

@@ -46,6 +46,9 @@ class DNSService {
     }
     final url = _removeDotAtEndOfString(listFieldData.last);
     log('DNSService::_parsingUrlFromDataResourceRecord:url: $url');
+    if (url.trim().isEmpty) {
+      throw NotFoundUrlException();
+    }
     return url;
   }