fix type of 'raw' attribute; remove width & height; update a comment

+## NEXT
+BREAKING CHANGES:
+* The `width` and `height` of `BarcodeCapture` have been removed, in favor of `size`.
+* The `raw` attribute is now `Object?` instead of `dynamic`, so that it participates in type promotion.
+
 ## 4.0.1
 Bugs fixed:
 * [iOS] Fixed a crash with a nil capture session when starting the camera. (thanks @navaronbracke !)

@@ -434,13 +434,18 @@ class MobileScannerController {
         final parsed = (data as List)
             .map((value) => Barcode.fromNative(value as Map))
             .toList();
+
+        final double? width = event['width'] as double?;
+        final double? height = event['height'] as double?;
+
         _barcodesController.add(
           BarcodeCapture(
             raw: data,
             barcodes: parsed,
             image: event['image'] as Uint8List?,
-            width: event['width'] as double?,
-            height: event['height'] as double?,
+            size: width == null || height == null
+                ? Size.zero
+                : Size(width, height),
           ),
         );
       case 'barcodeMac':

@@ -147,7 +147,9 @@ class Barcode {
   /// The SMS message that is embedded in the barcode.
   final SMS? sms;
 
-  /// The type of the [format] of the barcode.
+  /// The contextual type of the [format] of the barcode.
+  ///
+  /// For example: TYPE_TEXT, TYPE_PRODUCT, TYPE_URL, etc.
   ///
   /// For types that are recognized,
   /// but could not be parsed correctly, [BarcodeType.text] will be returned.

@@ -6,38 +6,25 @@ import 'package:mobile_scanner/src/objects/barcode.dart';
 /// This class represents a scanned barcode.
 class BarcodeCapture {
   /// Create a new [BarcodeCapture] instance.
-  BarcodeCapture({
+  const BarcodeCapture({
     this.barcodes = const <Barcode>[],
-    double? height,
     this.image,
     this.raw,
-    double? width,
-  }) : size =
-            width == null && height == null ? Size.zero : Size(width!, height!);
+    this.size = Size.zero,
+  });
 
   /// The list of scanned barcodes.
   final List<Barcode> barcodes;
 
   /// The bytes of the image that is embedded in the barcode.
   ///
-  /// This null if [MobileScannerController.returnImage] is false.
+  /// This null if [MobileScannerController.returnImage] is false,
+  /// or if there is no available image.
   final Uint8List? image;
 
   /// The raw data of the scanned barcode.
-  final dynamic raw; // TODO: this should be `Object?` instead of dynamic
+  final Object? raw;
 
   /// The size of the scanned barcode.
   final Size size;
-
-  /// The width of the scanned barcode.
-  ///
-  /// Prefer using `size.width` instead,
-  /// as this getter will be removed in the future.
-  double get width => size.width;
-
-  /// The height of the scanned barcode.
-  ///
-  /// Prefer using `size.height` instead,
-  /// as this getter will be removed in the future.
-  double get height => size.height;
 }