Merge commit '127503eb2cdd67126974bee304dde0f183300b84' into glitch-soc/merge-upstream

Conflicts:
- `app/helpers/accounts_helper.rb`:
  Conflict due to glitch-soc's option to hide followers count.
  Ported upstream changes.

Additional changes:
- `app/views/application/mailer/_account.html.haml`:
  Ported glitch-soc's option to hide followers count.
- `app/views/settings/flavours/show.html.haml`:
  Ported the `frontend_asset_url` helper change to glitch-soc.

app/serializers/rest/instance_serializer.rb

@@ -28,7 +28,7 @@ class REST::InstanceSerializer < ActiveModel::Serializer
       }
     else
       {
-        url: full_pack_url('media/images/preview.png'),
+        url: frontend_asset_url('images/preview.png'),
       }
     end
   end