fixed inconsistent placement of appbar title on iOS

lib/theming/dark_app_theme.dart

@@ -8,6 +8,7 @@ class DarkAppTheme {
       seedColor: marianumRed,
       brightness: Brightness.dark,
     ),
+    appBarTheme: const AppBarTheme(centerTitle: false),
     primaryColor: marianumRed,
   );
 }