fix: add early return guard for empty message in RPCView message handler

When message is empty after processing check messages, the handler now returns early
instead of proceeding to send an empty message through the chat service. This prevents
unnecessary API calls and potential errors from sending blank content.

src/snek/view/rpc.py

@@ -307,7 +307,8 @@ class RPCView(BaseView):
                     await self._queue_finalize_message(check_message["uid"])
                     return await self.update_message_text(check_message["uid"], message)
             
-        
+            if not message:
+                return        
 
             message = await self.services.chat.send(
                 self.user_uid, channel_uid, message, is_final