_preventDuplicateLabelClick(ev) {
      const __inputClickHandler = /** @param {Event} _ev */ _ev => {
        _ev.stopImmediatePropagation();
        this._inputNode.removeEventListener('click', __inputClickHandler);
      };
      this._inputNode.addEventListener('click', __inputClickHandler);
    }
The native platform fires an event for both the click on the label, and also
the redispatched click on the native input element.
This results in two click events arriving at the host, but we only want one.
This method prevents the duplicate click and ensures the correct isTrusted event
with the correct event.target arrives at the host.
@param {Event} ev
@protected