_dateTimeSwitchChange(e) {
      const target = e.target;
      this._showTimeView = target.getAttribute("key") === "Time";
      if (this._showTimeView) {
        this._currentTimeSlider = "hours";
      }
    }
Handles the date/time switch available in <code>phoneMode</code> to switch
between the date and time views.
@param {Event} e