feat: add zoomScale api for android and iOS

@@ -15,6 +15,7 @@ Breaking changes:
 
 Improvements:
 * Toggling the device torch now does nothing if the device has no torch, rather than throwing an error.
+* Removed `called stop while already stopped` messages.
 
 Features:
 * Added a new `placeholderBuilder` function to the `MobileScanner` widget to customize the preview placeholder.

@@ -238,9 +238,7 @@ public class MobileScannerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler,
     
     func toggleTorch(_ call: FlutterMethodCall, _ result: @escaping FlutterResult) {
         if (device == nil) {
-            result(FlutterError(code: "MobileScanner",
-                                    message: "Called toggleTorch() while stopped!",
-                                    details: nil))
+            result(nil)
             return
         }
         do {