With the help of a more complex method, this was decided earlier. I just wrote this topic so that BP would match the documentation.
You know how to achive all leaderboards ?
I think it's the same way :D
It's little bit complicated,but when you figure out,everything works fine.
Game Sparks Request Array - it's not at - StringArray
Alex Pozner
In the documentation, the data type for the friendIds is String:

But in the Blueprint editor, the data type is specified by the Game Sparks Request Array:Is this not a mistake?
It is not advisable to submit to the node Friends ids