Come up with long-term approach to exposing `copy(...)` method in binding classes

[krzema12]

Kotlin 2.0.20 compiler started producing warnings if the primary constructor of a data class is private: https://kotlinlang.org/docs/whatsnew2020.html#data-class-copy-function-to-have-the-same-visibility-as-constructor

As a short-term approach, we just suppress the warning, and the customers get a warning on the call site which is independent of this library. However, we'd like to keep exposing this method, so let's discuss what options we have to choose once starting using Kotlin 2.1.0.

Discussion: https://kotlinlang.slack.com/archives/C02UUATR7RC/p1724584851609139

[krzema12]

Let's see if someone has some interesting take on this: https://kotlinlang.slack.com/archives/C8C4JTXR7/p1729233924861659