Add @visibleForTesting for AndroidId._methodChannel

[AlexeyIWS]

Now not opportunity for mock testing of the lib

[nohli]

@AlexeyIWS you can see how to mock a response in the tests. Does that work for you?

[AlexeyIWS]

I think to be good that encapsulate channel name, for example:
https://github.com/fluttercommunity/plus_plugins/blob/main/packages/device_info_plus/device_info_plus_platform_interface/lib/method_channel/method_channel_device_info.dart