I don't consider it extrajudicial. Kushner should be charged with crimes in the united states. It is not extrajudicial just because the US is corrupt and won't prosecute kushner. Had that prosecution happened, everything the dutch did would be evidence against kushner.
I don't see why the dutch have any obligation to avoid monitoring a compromised phone that the US lets happen. The dutch have every right to know what the russians are getting from that phone.
You are picking the wrong case for your cause.