Allow all immutable List subclasses from Java 11

A previous commit specifically allowed one of the two subclasses used by
`List.of` and `List.copyOf`, but not the other, which can result in
unexpected errors and bugs. Add the other to the default allow list of
classes to avoid these.

core/src/main/resources/jenkins/security/whitelisted-classes.txt

@@ -105,6 +105,7 @@ java.util.HashMap
 java.util.HashSet
 java.util.Hashtable
 java.util.ImmutableCollections$List12
+java.util.ImmutableCollections$ListN
 java.util.LinkedHashMap
 java.util.LinkedHashSet
 java.util.LinkedList