fix: some theme issues

lib/models/isar/stack_theme.dart

@@ -1517,7 +1517,7 @@ class StackTheme {
               themeId: json["id"] as String,
             )
           : null
-      ..assetsV2 = version == 2
+      ..assetsV2 = version >= 2
           ? ThemeAssetsV2.fromJson(
               json: Map<String, dynamic>.from(json["assets"] as Map),
               applicationThemesDirectoryPath: applicationThemesDirectoryPath,
@@ -2222,6 +2222,36 @@ class ThemeAssetsV2 implements IThemeAssets {
 
     return result;
   }
+
+  @override
+  String toString() {
+    return 'ThemeAssetsV2('
+        'bellNew: $bellNew, '
+        'buy: $buy, '
+        'exchange: $exchange, '
+        'personaIncognito: $personaIncognito, '
+        'personaEasy: $personaEasy, '
+        'stack: $stack, '
+        'stackIcon: $stackIcon, '
+        'receive: $receive, '
+        'receivePending: $receivePending, '
+        'receiveCancelled: $receiveCancelled, '
+        'send: $send, '
+        'sendPending: $sendPending, '
+        'sendCancelled: $sendCancelled, '
+        'themeSelector: $themeSelector, '
+        'themePreview: $themePreview, '
+        'txExchange: $txExchange, '
+        'txExchangePending: $txExchangePending, '
+        'txExchangeFailed: $txExchangeFailed, '
+        'loadingGif: $loadingGif, '
+        'background: $background, '
+        'coinPlaceholder: $coinPlaceholder, '
+        'coinIcons: $coinIcons, '
+        'coinImages: $coinImages, '
+        'coinSecondaryImages: $coinSecondaryImages'
+        ')';
+  }
 }
 
 abstract class IThemeAssets {

lib/pages_desktop_specific/settings/settings_menu/appearance_settings/appearance_settings.dart

@@ -177,7 +177,7 @@ class ThemeToggle extends ConsumerStatefulWidget {
 
 class _ThemeToggle extends ConsumerState<ThemeToggle> {
   late final StreamSubscription<void> _subscription;
-  late int _current;
+  int _current = 0;
 
   List<Tuple3<String, String, String>> installedThemeIdNames = [];