[TIMOB-6489] Android: Only set basic auth on web view if the proxy is of type WebViewProxy

       <modules>
           <module>ti.sample</module>
       </modules>
   

   var window = Ti.UI.createWindow({
   	backgroundColor:'white'
   });
   var label = Ti.UI.createLabel();
   window.add(label);
   window.open();
   
   var webview = require('ti.sample');
   Ti.API.info("module is => " + webview);
   
   label.text = webview.example();
   
   Ti.API.info("module exampleProp is => " + webview.exampleProp);
   webview.exampleProp = "This is a test value";
   
   if (Ti.Platform.name == "android") {
   	var proxy = webview.createExample({
   		message: "Creating an example Proxy",
   		backgroundColor: "red",
   		width: 100,
   		height: 100,
   		top: 100,
   		left: 150
   	});
   
   	proxy.printMessage("Hello world!");
   	proxy.message = "Hi world!.  It's me again.";
   	proxy.printMessage("Hello world!");
   	window.add(proxy);
   }