[BugFix] fix num_running_requests in cuda_graph (#3457)

* fix cuda_grpah

* add note

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Co-authored-by: RAM <gstian5555@outlook.com>

fastdeploy/worker/gpu_model_runner.py

@@ -1594,6 +1594,10 @@ class GPUModelRunner(ModelRunnerBase):
         In FastDeploy, almost all input tensors have a buffer. So, just keep the buffer clean when replaying the CUDA graph with the padded batch.
         """
         # In init_attention_metadata, the decode buffer has already been cleared
+
+        # To adapt to CUDA Graph, keep the forward pass at the maximum batch size.
+        if self.use_cudagraph:
+            self.forward_meta.seq_lens_this_time = self.seq_lens_this_time_buffer
         return
 
     def _init_image_preprocess(self) -> None: