You can call any function that has been marked as BlueprintCallable in the code via Blueprints.
The “UpdatePrimitveDistanceFieldSceneData_GameThread” function has not been exposed to blueprints in the code. You can, however write a custom C++ function that calls the function, and expose that function to Blueprints. (You will need C++, though)
This may help you write C++ in a Blueprint project (never tried it, but sounds cool):
But I still do recommend that you make your project a C++ project instead of Blueprint-only, because of little things like this.