show username when names are empty

management/lib/models/user.dart

@@ -31,7 +31,9 @@ class User {
         scope: map['scope'],
       );
 
-  String get fullName => name != null && surname != null ? '$name $surname' : username;
+  String get fullName => name != null && name!.isNotEmpty && surname != null && surname!.isNotEmpty
+      ? '$name $surname'
+      : username;
 
   Scope? get scopeObj {
     if (scope == 'user') {