Show plugins setting button even if no enabled setting

In the list of plugins a button to the settings is shown only if the plugin has an enabled setting.

https://github.com/discourse/discourse/blob/80d42b4ea2ee14e8e5d6bc5176e9835052595dfc/app/assets/javascripts/admin/templates/plugins-index.hbs#L51-L53

It would be slightly less efficient to filter all settings, but it’s not like the page is a frequently used one.