K2 | Add support for data types inherited from extended interface

[Lavmee]

Currently, types inherited extended interface are not properly generated.

A small example:

interface A { name : String }

type Example implements A {
    name: String
}

extend interface A {
    age: Int
}

extend type Example {
    age: Int
}

generates the following kotlin class with no override original interface fields (generated interface is correct):

public class Example(
 ...
) : A {

  val name: String
    get() = __name.invoke()

  override val age: Int
    get() = __age.invoke()
...
}