Add `getLastTrialDataUtility` function from GearShift

[RobertGemmaJr]

/**
 * Retrieves the data object from the last trial in JsPsych
 * @param {JsPsych} jsPsych jsPsych instance being used to run the task
 * @returns {Object}
 */
export function getLastTrialData(jsPsych) {
  const dataCollection = jsPsych.data.getLastTrialData();
  return dataCollection.trials[0];
}