Add isListening function

[JulienLecoq]

Is your feature request related to a problem? Please describe. Yes, I would like to check if the Speech Recognition plugin is listening to perform action depending if it is listening or not.

Describe the solution you'd like Add a method isListening that should return true if the plugin is listening to the user voice.

[OnlinePage]

please this is very important, without isListenting its become hard to track whether speech recognition is still going on or when finished!! @jcesarmobile

[prakash03yes]

Yeah On Ios I dont know , when listening stopped. :(

[jcesarmobile]

it was implemented on https://github.com/capacitor-community/speech-recognition/pull/83 and released on 5.1.0