[BUG] Possibly-incorrect check on ring buffers for WaveNet

[sdatkinson]

This assertion might be incorrect:

https://github.com/sdatkinson/NeuralAmpModelerCore/blob/846968710a670d662b15e449edba852d747d748e/NAM/wavenet.cpp#L159-L166

I don't think that it should be the receptive field of the layer array, but the r.f. of the single-largest layer.

Worth thinking about a unit test that could assert this. I think that a WaveNet that implements a delay would work--It shoudl be able to replay the delay even if the receptive field for the whole model is longer than the length of any single ring buffer because of how the information should cascade.