refactor(mobile): app settings (#7749)

* refactor(mobile): app settings

* Font size

* refactor(mobile): backup settings ui (#7771)

* refactor: SettingsButtonListTile

* refactor: Backup settings to App settings

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>

* fix: invalidate appsettingsprovider on timeline setting change

* styling

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>
Co-authored-by: Alex Tran <alex.tran1502@gmail.com>

mobile/lib/modules/settings/views/settings_sub_page.dart

@@ -0,0 +1,22 @@
+import 'package:auto_route/auto_route.dart';
+import 'package:easy_localization/easy_localization.dart';
+import 'package:flutter/material.dart';
+import 'package:immich_mobile/modules/settings/views/settings_page.dart';
+
+@RoutePage()
+class SettingsSubPage extends StatelessWidget {
+  const SettingsSubPage(this.section, {super.key});
+
+  final SettingSection section;
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        centerTitle: false,
+        title: Text(section.title).tr(),
+      ),
+      body: section.widget,
+    );
+  }
+}