`SegArray.unregister()` does not remove all components of an attached SegArray from registry

[joshmarshall1]

When registering a SegArray on the server, calling .unregister() on the original will remove all components from the symbol table. However, attaching to a registered SegArray then calling .unregister() on the attached version will only remove the lengths component from the symbol table, leaving values and segments registered.