[Bugfix] Fix tokenizer_manager not getting 400 when req is too long (#3678)

Co-authored-by: voidxb <unkown>

python/sglang/srt/managers/scheduler.py

@@ -683,6 +683,8 @@ class Scheduler:
             self.server_args.allow_auto_truncate,
         )
         if error_msg:
+            req.origin_input_ids = [0]
+            req.sampling_params.max_new_tokens = 0
             self.waiting_queue.append(req)
             return