refactor(metadata): move cover resolution to extensions

lib/screens/settings/metadata_settings_page.dart

@@ -52,15 +52,6 @@ class MetadataSettingsPage extends ConsumerWidget {
                         settings.artistTagMode,
                       ),
                     ),
-                    SettingsSwitchItem(
-                      icon: Icons.image,
-                      title: context.l10n.optionsMaxQualityCover,
-                      subtitle: context.l10n.optionsMaxQualityCoverSubtitle,
-                      value: settings.maxQualityCover,
-                      onChanged: (v) => ref
-                          .read(settingsProvider.notifier)
-                          .setMaxQualityCover(v),
-                    ),
                     SettingsSwitchItem(
                       icon: Icons.graphic_eq,
                       title: context.l10n.optionsReplayGain,

lib/screens/settings/settings_search_catalog.dart

@@ -233,12 +233,6 @@ class SettingsSearchCatalog {
           title: l10n.optionsArtistTagMode,
           keywords: const ['artist separator', 'multiple artists'],
         ),
-        SettingsSearchEntry(
-          icon: Icons.image,
-          title: l10n.optionsMaxQualityCover,
-          subtitle: l10n.optionsMaxQualityCoverSubtitle,
-          keywords: const ['artwork', 'album art', 'cover size'],
-        ),
         SettingsSearchEntry(
           icon: Icons.graphic_eq,
           title: l10n.optionsReplayGain,