Use final_internal_class with annotation_exclude

[martin-ro]

Removes final_class and uses instead

 "final_internal_class": {
      "annotation_include": [],
      "annotation_exclude": ["internal"]
    },

final_class is an alias for final_internal_class as explained here and in code here.

So using final_internal_class with "annotation_exclude": ["internal"] will still make all classes final unless we add @internal. This is handy if you want to extend classe in your project.