fix check for permission state

@@ -45,7 +45,7 @@ class MobileScannerPermissions {
         return if (hasPermission) {
             1
         } else {
-            0
+            2
         }
     }
 

@@ -189,8 +189,9 @@ class MobileScannerController {
       final MobileScannerState state;
 
       try {
-        state = MobileScannerState
-            .values[await _methodChannel.invokeMethod('state') as int? ?? 0];
+        state = MobileScannerState.fromRawValue(
+          await _methodChannel.invokeMethod('state') as int? ?? 0,
+        );
       } on PlatformException catch (error) {
         isStarting = false;