Update apppreferences.js
Update apppreferences.js

When building I received an "Unexpected token &&" error which, as far as I can tell, is a result of the following lines:

```
if (successCallback !== undefined
		&& typeof successCallback !== function && typeof errorCallback !== function
		&& dict === undefined && key === undefined
		&& promiseLib
	)
```

The proposed change encapsulates the 'function' typeof checks in quotes to fix the fault.
vladimir-kotikov/cordova-app-preferences,adobe-rnd/me.apla.cordova.app-preferences,micky2be/me.apla.cordova.app-preferences,micky2be/me.apla.cordova.app-preferences,apla/me.apla.cordova.app-preferences,vladimir-kotikov/cordova-app-preferences,micky2be/me.apla.cordova.app-preferences,tripodsan/me.apla.cordova.app-preferences,tripodsan/me.apla.cordova.app-preferences,daxko/me.apla.cordova.app-preferences,tripodsan/me.apla.cordova.app-preferences,xlongtang/me.apla.cordova.app-preferences,daxko/me.apla.cordova.app-preferences,apla/me.apla.cordova.app-preferences,daxko/me.apla.cordova.app-preferences,adobe-rnd/me.apla.cordova.app-preferences,xlongtang/me.apla.cordova.app-preferences,apla/me.apla.cordova.app-preferences,tripodsan/me.apla.cordova.app-preferences,apla/me.apla.cordova.app-preferences,daxko/me.apla.cordova.app-preferences,daxko/me.apla.cordova.app-preferences,xlongtang/me.apla.cordova.app-preferences,vladimir-kotikov/cordova-app-preferences,adobe-rnd/me.apla.cordova.app-preferences,vladimir-kotikov/cordova-app-preferences,micky2be/me.apla.cordova.app-preferences,apla/me.apla.cordova.app-preferences,vladimir-kotikov/cordova-app-preferences,adobe-rnd/me.apla.cordova.app-preferences,xlongtang/me.apla.cordova.app-preferences,xlongtang/me.apla.cordova.app-preferences