Fix return value when fwding msgs if some are missing
Fix return value when fwding msgs if some are missing

It was supposed to return None for the spots were it failed to fwd
a message, but instead only those that were present were returned,
because we were iterating over the wrong object (dict and not list).

LonamiWebs/Telethon,LonamiWebs/Telethon,LonamiWebs/Telethon,LonamiWebs/Telethon