function selectCardsPerHandHandler() {
  game.GAME_STATE.num_cards_per_hand =
      Number.parseInt(document.getElementById('select-cards-per-hand').value);
  simulateGameHandler(true);
  ui.updatePredictionInputs();
  ui.displayBatches([]);
  ui.disablePredictButton();
  ui.displayPrediction('New model needs to be trained');
}
Updates the game constant controlling the number of cards per hand and
clears UI.