use a single try catch block for the camera permission

@@ -94,42 +94,29 @@ class MethodChannelMobileScanner extends MobileScannerPlatform {
   ///
   /// Throws a [MobileScannerException] if the permission is not granted.
   Future<void> _requestCameraPermission() async {
-    final MobileScannerAuthorizationState authorizationState;
-
     try {
-      authorizationState = MobileScannerAuthorizationState.fromRawValue(
+      final MobileScannerAuthorizationState authorizationState =
+          MobileScannerAuthorizationState.fromRawValue(
         await methodChannel.invokeMethod<int>('state') ?? 0,
       );
-    } on PlatformException catch (error) {
-      // If the permission state is invalid, that is an error.
-      throw MobileScannerException(
-        errorCode: MobileScannerErrorCode.genericError,
-        errorDetails: MobileScannerErrorDetails(
-          code: error.code,
-          details: error.details as Object?,
-          message: error.message,
-        ),
-      );
-    }
 
       switch (authorizationState) {
+        // Authorization was already granted, no need to request it again.
         case MobileScannerAuthorizationState.authorized:
-        return; // Already authorized.
+          return;
         // Android does not have an undetermined authorization state.
         // So if the permission was denied, request it again.
         case MobileScannerAuthorizationState.denied:
         case MobileScannerAuthorizationState.undetermined:
-        try {
-          final bool granted =
+          final bool permissionGranted =
               await methodChannel.invokeMethod<bool>('request') ?? false;
 
-          if (granted) {
-            return; // Authorization was granted.
-          }
-
+          if (!permissionGranted) {
             throw const MobileScannerException(
               errorCode: MobileScannerErrorCode.permissionDenied,
             );
+          }
+      }
     } on PlatformException catch (error) {
       // If the permission state is invalid, that is an error.
       throw MobileScannerException(
@@ -142,7 +129,6 @@ class MethodChannelMobileScanner extends MobileScannerPlatform {
       );
     }
   }
-  }
 
   @override
   Stream<BarcodeCapture?> get barcodesStream {