[iOS] zeroconf.close never invokes success/error callback

[antweb]

The behaviour of zeroconf.close() is inconsistent between Android and iOS. While Android sends a plugin result, iOS does not. As the Android version uses a background thread, it is necessary to rely on the callback to make sure the action has finished.

A simple solution would be to send a success plugin result in iOS as well.

[becvert]

ok I'll have a look sometime. thank you

[emcniece]

@becvert I can PR today!

[becvert]

#53 is fixing the close method actually.
I think the same could be apply to stop indeed
@emcniece go ahead with merging this into 1.3.0. thanks 👍