fix: localized base-10 data size units

packages/ubuntu_desktop_installer/test/widgets/storage_size_box_test.dart

@@ -81,7 +81,7 @@ void main() {
         ),
       );
       expect(
-          find.widgetWithText(SpinBox, (5 * 1024).toString()), findsOneWidget);
+          find.widgetWithText(SpinBox, (5 * 1000).toString()), findsOneWidget);
     });
 
     testWidgets('in kilobytes', (tester) async {
@@ -94,7 +94,7 @@ void main() {
           onUnitSelected: (_) {},
         ),
       );
-      expect(find.widgetWithText(SpinBox, (5 * 1024 * 1024).toString()),
+      expect(find.widgetWithText(SpinBox, (5 * 1000 * 1000).toString()),
           findsOneWidget);
     });
   });

packages/ubuntu_utils/lib/src/data_size.dart

@@ -3,9 +3,9 @@ import 'dart:math' as math;
 enum DataUnit { bytes, kilobytes, megabytes, gigabytes }
 
 int toBytes(double size, DataUnit unit) {
-  return (size * math.pow(1024, unit.index)).round();
+  return (size * math.pow(1000, unit.index)).round();
 }
 
 double fromBytes(int size, DataUnit unit) {
-  return size / math.pow(1024, unit.index).toInt();
+  return size / math.pow(1000, unit.index).toInt();
 }

packages/ubuntu_utils/test/data_size_test.dart

@@ -8,17 +8,17 @@ void main() {
   });
 
   test('kilobytes', () {
-    expect(toBytes(1, DataUnit.kilobytes), equals(1024));
-    expect(fromBytes(1024, DataUnit.kilobytes), equals(1));
+    expect(toBytes(1, DataUnit.kilobytes), equals(1000));
+    expect(fromBytes(1000, DataUnit.kilobytes), equals(1));
   });
 
   test('megabytes', () {
-    expect(toBytes(1, DataUnit.megabytes), equals(1024 * 1024));
-    expect(fromBytes(1024 * 1024, DataUnit.megabytes), equals(1));
+    expect(toBytes(1, DataUnit.megabytes), equals(1000 * 1000));
+    expect(fromBytes(1000 * 1000, DataUnit.megabytes), equals(1));
   });
 
   test('bytes', () {
-    expect(toBytes(1, DataUnit.gigabytes), equals(1024 * 1024 * 1024));
-    expect(fromBytes(1024 * 1024 * 1024, DataUnit.gigabytes), equals(1));
+    expect(toBytes(1, DataUnit.gigabytes), equals(1000 * 1000 * 1000));
+    expect(fromBytes(1000 * 1000 * 1000, DataUnit.gigabytes), equals(1));
   });
 }