Wait for *all* players to receive the texture before using it.
Previously this would wait for *any* player to receive the texture.
This works fine in singleplayer (or on pre-5.5,
where dynamic_add_media would block until all players have received the texture),
but it may fail otherwise:
Either entity textures won't be available in time,
or, even worse, the HUD texture is unavailable.
Both produce an error in chat for clients.
