Return the correct entity from .get_entity(username)
Return the correct entity from .get_entity(username)

The precedence of the or operator made the check succeed always
out of pure luck, since `''.lower()` would never be the chosen
username, but a present username is truthy.

This presumably worked because Telegram only returns one result
from the call, or puts the right entity the first one.

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