Export CreateObservableOptions type so one can extend makeObservable

[ahoisl]

If you want to extend or create a custom function using makeObservable, you may want to also pass in CreateObservableOptions to that custom function.
The CreateObservableOptions type is not exported though and must be imported from dist/api/observable or dist/internal - both unresolvable locations at pack time (according to dependency cruiser).

Would be great if we can also export that type.

Suggested code change in PR #2717

[danielkcz]

Technically, you should be able to access that type with Parameters<typeof makeObservable>[0], but I agree that exporting it won't do any harm.