Add ValueExtractor for ArgumentValue

[bduisenov]

Validation annotations on ArgumentValue are not working as there's no ValueExtractor provided.
For example, this code ArgumentValue<@NotBlank @Size(min = 2, max = 500) String> name will not work as expected.

Adding ValueExtractor will solve the issue

@UnwrapByDefault
public class ArgumentValueExtractor implements ValueExtractor<ArgumentValue<@ExtractedValue ?>> {

    @Override
    public void extractValues(ArgumentValue<?> originalValue, ValueReceiver receiver) {
        if (originalValue.isPresent()) {
            receiver.value(null, originalValue.value());
        }
    }
}

#736

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[rstoyanchev]

Thanks for the PR.

We probably don't want to put a helper class of this kind at the top of the data package. It could go further below under ~.data.method.annotation.support where we already have other validation support. A test to prove this works would also be nice to have, probably in ValidationHelperTests.

Let me know if you would you like to shape the changes further based on this, or if not we can take it from here.

[bduisenov]

hey @rstoyanchev
Thanks for your feedback. I'm happy to adjust the code.

[bduisenov]

hey @rstoyanchev, please take another look.

[rstoyanchev]

Thanks for the changes.