HippoNodeTypeRegistry.externalRegistered method doesn't properly suppress persisting node type changes from a cluster event

REPO-2305 added special handling to suppress the unnecessary, and sometimes problematic, behavior in Jackrabbit to also (again) persist node type changes triggered on a different cluster node, via its cluster events.

Those broadcasted node type changes already were persisted, so doing it again is totally redundant, and the cluster event notification really only needs to update to in memory node type registry on the receiving instance.

The implementation in REPO-2305 however contained a small but important glitch in the handling of the externalRegistered method (which is for new node types), unlike the externalReRegistered (for updated node types) and externalUnregistered (for removed node types) methods.

The externalRegistered override method for the Jackrabbit NodeTypeRegistry also (still) called the super method without suppressing the persisting of the change. So effectively, for new node types the intended behavior change just didn't work at all!

This issue fixes the glitch by removing that erroneous extra super method call.

This fix also will be back ported to all current supported versions, but primarily is needed for 14.2.3+, as we first encountered this as (part of) a problem for upgrading to 14.3.x (CMS-14073)