[xpu] fix interrupt error (#7805)

Author: zhupengyang

fastdeploy/worker/xpu_model_runner.py

@@ -1300,6 +1300,10 @@ class at the server level, which is too granular for ModelRunner.
             # 2. Padding inputs for cuda grph
             self.padding_cudagraph_inputs()
 
+            num_tokens = self.share_inputs["ids_remove_padding"].shape[0]
+            if not self.parallel_config.enable_expert_parallel and num_tokens <= 0:
+                return None
+
             # NOTE(wufeisheng): If `not_need_stop`` is False, it means the current worker is in an idle state.
             # This logic is not used in TP (Tensor Parallelism) mode. However, in EP (Expert Parallelism) mode,
             # when there is data on other runner, the current runner is required to execute part of the model.