Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `app/controllers/admin/base_controller.rb`:
  Minor conflict caused by glitch-soc's theming system.
- `app/javascript/mastodon/initial_state.js`:
  Minor conflict caused by glitch-soc making use of max_toot_chars.
- `app/models/form/admin_settings.rb`:
  Minor conflict caused by glitch-soc's theming system.
- `app/models/trends.rb`:
  Minor conflict caused by glitch-soc having more granular
  notification settings for trends.
- `app/views/admin/accounts/index.html.haml`:
  Minor conflict caused by glitch-soc's theming system.
- `app/views/admin/instances/show.html.haml`:
  Minor conflict caused by glitch-soc's theming system.
- `app/views/layouts/application.html.haml`:
  Minor conflict caused by glitch-soc's theming system.
- `app/views/settings/preferences/notifications/show.html.haml`:
  Minor conflict caused by glitch-soc having more granular
  notification settings for trends.
- `config/navigation.rb`:
  Minor conflict caused by glitch-soc having additional
  navigation items for the theming system while upstream
  slightly changed every line.

app/controllers/admin/custom_emojis_controller.rb

@@ -29,6 +29,8 @@ module Admin
     end
 
     def batch
+      authorize :custom_emoji, :index?
+
       @form = Form::CustomEmojiBatch.new(form_custom_emoji_batch_params.merge(current_account: current_account, action: action_from_button))
       @form.save
     rescue ActionController::ParameterMissing