add url to Metadata.build_tags call

If static_fe is enabled, going to https://pleroma/notice/some-id
results in

<meta content="https://pleroma/users/someuser" property="og:url">

With this fix, it is

<meta content="https://pleroma/notice/some-id" property="og:url">

Additionally, Pleroma.Web.Metadata.Providers.OpenGraph now
generates meta tags for attachments in the post.

lib/pleroma/web/static_fe/static_fe_controller.ex

@@ -25,7 +25,15 @@ defmodule Pleroma.Web.StaticFE.StaticFEController do
          true <- Visibility.is_public?(activity.object),
          {_, true} <- {:visible?, Visibility.visible_for_user?(activity, _reading_user = nil)},
          %User{} = user <- User.get_by_ap_id(activity.object.data["actor"]) do
-      meta = Metadata.build_tags(%{activity_id: notice_id, object: activity.object, user: user})
+      url = Helpers.url(conn) <> conn.request_path
+
+      meta =
+        Metadata.build_tags(%{
+          activity_id: notice_id,
+          object: activity.object,
+          user: user,
+          url: url
+        })
 
       timeline =
         activity.object.data["context"]