text: Title: Unused os.path.join in chat_photo.py
  Body: I was looking at the aiogram code on github accidentally found that `os.path.join` is not used here, which is suspicious.
  
  https://github.com/aiogram/aiogram/blob/df294e579f104e2ae7e9f37b0c69490782d33091/aiogram/types/chat_photo.py#L62-L63