Previously, if the parent class was in Java code and the subclass in
Kotlin, the opt-in usage error would not be reported for the subclass.
The problem was that the extractClassFromArgument function couldn't get
the class type from Java code. It was looking for a ConeClassLikeType,
but found a ConeFlexibleType instead.
#KT-60258 Fixed
Anastasia.Nekrasova