Remove messy subclassing in the TelegramClient

Since it was easy to cause MRO inconsistencies, and it's
not really needed now that self is type hinted as the client.

telethon/client/chats.py

@@ -3,7 +3,6 @@ import itertools
 import string
 import typing
 
-from .users import UserMethods
 from .. import helpers, utils, hints
 from ..requestiter import RequestIter
 from ..tl import types, functions, custom
@@ -345,7 +344,7 @@ class _ProfilePhotoIter(RequestIter):
                 self.request.offset_id = result.messages[-1].id
 
 
-class ChatMethods(UserMethods):
+class ChatMethods:
 
     # region Public methods