Wrong error returned in network_interfaces in GenDiagHandler

[marcemmers]

I've tried out this project yesterday trying to connect it to https://github.com/matter-js/python-matter-server and had quite a hard time with it as it's the first time I did anything with Matter at all. We were running this on a linux system but I don't think that matters a lot.

It turns out that in the network_interfaces function of GenDiagHandler the return type in the ArrayAttributeRead::ReadOne was wrong. Changing that ErrorCode::InvalidAction into ErrorCode::ConstraintError fixed it.

I am willing to make a PR for this change, but I am not confident enough that this is really the right change or if this would break other things.

[ivmarkov]

@marcemmers Please open a PR for this. Very likely you are right that the correct code should be "Constraint Error".
We are slowly enabling all Project Chip Integration Tests, but the General Diagnostic ones I think are not yet enabled.