Preload thread mutes/bookmarks in get_context

Also removes filtering for creates (was done on the database side
already) and filtering for the requested activity (moved to the database
side) from application side.

lib/pleroma/web/mastodon_api/mastodon_api_controller.ex

@@ -497,12 +497,9 @@ defmodule Pleroma.Web.MastodonAPI.MastodonAPIController do
          activities <-
            ActivityPub.fetch_activities_for_context(activity.data["context"], %{
              "blocking_user" => user,
-             "user" => user
+             "user" => user,
+             "exclude_id" => activity.id
            }),
-         activities <-
-           activities |> Enum.filter(fn %{id: aid} -> to_string(aid) != to_string(id) end),
-         activities <-
-           activities |> Enum.filter(fn %{data: %{"type" => type}} -> type == "Create" end),
          grouped_activities <- Enum.group_by(activities, fn %{id: id} -> id < activity.id end) do
       result = %{
         ancestors: