go/registry: Relax the update check to allow nodes to opt into more runtimes

[Yawning]

Currently when a node update's it's registration, the list of runtimes needs to be identical (except for the attestation). This causes problems when a node that previously was not of a class that requires runtimes in the node descriptor (eg: a validator) wishes to opt-in to also being one that does (eg: a validator + compute worker).

The check here probably should also be relaxed to allow adding runtimes to the node descriptor on registration update.