[TIMOB-27862] Android: Add callback support to Ti.Platform.openURL()

*Summary:* On Android, the Ti.Platform.openURL() method only supports the URL argument. The 2 optional arguments, "options" dictionary and callback, are ignored and only supported on iOS. https://docs.appcelerator.com/platform/latest/#!/api/Titanium.Platform-method-openURL We should add support for the callback argument for consistency with iOS.

// Add support for the callback argument.
var result = Ti.Platform.openURL("https://www.google.com", function(e) {
	Ti.API.info("### openURL() callback event.success: " + e.success);
});

// We should still support returned boolean for backward compatibility.
Ti.API.info("### openURL() returned: " + result);

*Note:* The "options" dictionary should continue to be ignored since it only supports iOS settings. Meaning that the below should work on Android without issue.

var result = Ti.Platform.openURL("https://www.google.com", {/* Ignore Me */}, function(e) {
	Ti.API.info("### openURL() callback event.success: " + e.success);
});