I want to override the default Registration validator that is enabled when the Registration feature is added.
I have added my own CustomRegistrationValidator as per the ServiceStack documentation (basic rules for now, to be expanded later):

```
public class CustomRegistrationValidator : RegistrationValidator
    {
        public CustomRegistrationValidator()
        {
            RuleSet(ApplyTo.Post, () =>
            {
                RuleFor(x => x.FirstName).NotEmpty();
                RuleFor(x => x.LastName).NotEmpty();
                RuleFor(x => x.Email).NotEmpty();
                RuleFor(x => x.Password).NotEmpty();
            });
        }
    }

```

I have overridden the default registration validator in my Configure method as per the following snippet:

```
Plugins.Add(new AuthFeature(
            () => new AuthUserSession(),
                  new IAuthProvider[] { new BasicAuthProvider(),
                  new CredentialsAuthProvider()
                }));

            Plugins.Add(new ValidationFeature());
            Plugins.Add(new RegistrationFeature());

            RegisterAs<CustomRegistrationValidator, IValidator<Register>>();
            container.RegisterValidators(typeof(AppHost).Assembly);

```

However, the validator never appears to execute, thus I can register new users with invalid details.

I am using the latest version of ServiceStack V4.0.22

Is this a major ServiceStack bug or is this feature no longer available with the latest version of ServiceStack?

Thank you in advance for any help with this.

Regards
John