Explicitly check for port

The setup uses `\OCP\IRequest::getInsecureServerHost` which in some cases can also include a port. This makes the trusted domain check fail thus.

I've decided to add this here that way because adjusting the setup would require parsing the host properly. This is not something that can be done very good in PHP. Check the following example for why `parse_url` is not our friend: https://3v4l.org/k501Z