[Codegen] Remove redundancies in interfaces generated by the Java and TypeScript codegens

Currently, the Interfaces generated by the Java and TypeScript codegens contain redundancies in their fields caused by fields being passed down the inheritance hierarchy of the classes by the codegen.

Two possible solutions:
a) Mark inherited fields with a flag like `is_inherited`
b) Make sure that subclasses get generated after parent classes (might already be the case?). This means you can store which fields are from which class and subclasses can check if a class it is inheriting from already has the field that is currently being declared