opt: cache clean

lib/pages/setting/models/extra_settings.dart

@@ -595,19 +595,10 @@ List<SettingsModel> get extraSettings => [
       onTap: _showProxyDialog,
     ),
   ),
-  const SwitchModel(
-    title: '自动清除缓存',
-    subtitle: '每次启动时清除缓存',
-    leading: Icon(Icons.auto_delete_outlined),
-    setKey: SettingBoxKey.autoClearCache,
-    defaultVal: false,
-  ),
   NormalModel(
     title: '最大缓存大小',
-    getSubtitle: () {
-      final num = Pref.maxCacheSize;
-      return '当前最大缓存大小: 「${num == 0 ? '无限' : CacheManager.formatSize(Pref.maxCacheSize)}」';
-    },
+    getSubtitle: () =>
+        '当前最大缓存大小: 「${CacheManager.formatSize(Pref.maxCacheSize)}」',
     leading: const Icon(Icons.delete_outlined),
     onTap: _showCacheDialog,
   ),