Fix translations for changing theme (#25340)

app/views/settings/preferences/appearance/show.html.haml

@@ -10,7 +10,7 @@
       = f.input :locale, collection: I18n.available_locales, wrapper: :with_label, include_blank: false, label_method: lambda { |locale| native_locale_name(locale) }, selected: I18n.locale, hint: false
     .fields-group.fields-row__column.fields-row__column-6
       = f.simple_fields_for :settings, current_user.settings do |ff|
-        = ff.input :theme, collection: Themes.instance.names, label_method: lambda { |theme| I18n.t("themes.#{theme}", default: theme) }, wrapper: :with_label, include_blank: false, hint: false
+        = ff.input :theme, collection: Themes.instance.names, label_method: lambda { |theme| I18n.t("themes.#{theme}", default: theme) }, wrapper: :with_label, label: I18n.t('simple_form.labels.defaults.setting_theme'), include_blank: false, hint: false
 
   - unless I18n.locale == :en
     .flash-message.translation-prompt