Simplify type check / pattern matching

Co-authored-by: R. Miles McCain <[email protected]>

platform/lib/platform/updates.ex

@@ -308,7 +308,7 @@ defmodule Platform.Updates do
   @doc """
   Helper API function that takes attribute change information and uses it to create an Update changeset. Requires 'explanation' to be in attrs.
   """
-  def change_from_media_creation(%Media{} = media, user_or_token) when is_struct(user_or_token, User) or is_struct(user_or_token, APIToken) do
+  def change_from_media_creation(%Media{} = media, %_{} = user_or_token) when user_or_token in [%User{}, %APIToken{}] do
     change_update(
       %Update{},
       media,