Add "iosRestartPolling" method

[rostopira]

Sometimes I'm receiving "Tag connection lost" even if tag isn't moving
And I have to execute over 400 commands in a row, so starting again or reconnecting isn't an option, since you can't get rid of all those "awesome" animation and it takes a second on each exception.
I've added iosRestartPolling method which calls NFCTagReaderSession.restartPolling() in Swift and it solves the issue for me.
I hope this will help someone else

[Harry-Chen]

Thanks!

[rostopira]

Usage example:

try {
  // Do something like transceive
} on PlatformException catch (e) {
  if (e.details != "Tag connection lost") {
    await reconnectToTag();
    await tryThisAgain();
  } else {
    await FlutterNfcKit.iosRestartPolling();
    await tryThisAgain();
  }
}

[rostopira]

@Harry-Chen any plans to push new version to pubdev?