MastoAPI: Add unimplemented status card endpoint.

lib/pleroma/web/mastodon_api/mastodon_api_controller.ex

@@ -624,6 +624,11 @@ def empty_array(conn, _) do
     json(conn, [])
   end
 
+  def empty_object(conn, _) do
+    Logger.debug("Unimplemented, returning an empty object")
+    json(conn, %{})
+  end
+
   def render_notification(user, %{id: id, activity: activity, inserted_at: created_at} = _params) do
     actor = User.get_cached_by_ap_id(activity.data["actor"])
     created_at = NaiveDateTime.to_iso8601(created_at)

lib/pleroma/web/router.ex

@@ -132,6 +132,7 @@ def user_fetcher(username) do
 
     get "/statuses/:id", MastodonAPIController, :get_status
     get "/statuses/:id/context", MastodonAPIController, :get_context
+    get "/statuses/:id/card", MastodonAPIController, :empty_object
     get "/statuses/:id/favourited_by", MastodonAPIController, :favourited_by
     get "/statuses/:id/reblogged_by", MastodonAPIController, :reblogged_by