refactor(channels/generic): short condition

channels/generic/websocket.py

@@ -200,7 +200,7 @@ async def websocket_receive(self, message):
         Called when a WebSocket frame is received. Decodes it and passes it
         to receive().
         """
-        if "text" in message and message["text"] is not None:
+        if message.get("text") is not None:
             await self.receive(text_data=message["text"])
         else:
             await self.receive(bytes_data=message["bytes"])