Fixes bug with following/unfollowing system theme

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/src/services/reactive_theme/arcane_theme.dart

@@ -0,0 +1,23 @@
+import "package:flutter/material.dart";
+
+class ArcaneTheme extends InheritedWidget {
+  final ThemeMode themeMode;
+  final bool followSystem;
+
+  const ArcaneTheme({
+    required this.themeMode,
+    required this.followSystem,
+    required super.child,
+    super.key,
+  });
+
+  static ArcaneTheme? of(BuildContext context) {
+    return context.dependOnInheritedWidgetOfExactType<ArcaneTheme>();
+  }
+
+  @override
+  bool updateShouldNotify(ArcaneTheme oldWidget) {
+    return themeMode != oldWidget.themeMode ||
+        followSystem != oldWidget.followSystem;
+  }
+}