fix(agents): update telegram bot example config (#516)

When using Mixins, Mixin config should be a parent class for
`AgentService` Config types.

Co-authored-by: Douglas Reid <doug@steamship.com>

Author: douglas-reid

src/steamship/agents/examples/telegram_bot.py

@@ -49,7 +49,7 @@ class TelegramBot(AgentService):
 
     """
 
-    class TelegramBotConfig(Config):
+    class TelegramBotConfig(TelegramTransportConfig):
         bot_token: str = Field(description="The secret token for your Telegram bot")
 
     @classmethod