fix mooncake layerwise connector

Signed-off-by: liziyu <liziyu16@huawei.com>

Author: liziyu179

vllm_ascend/distributed/mooncake_layerwise_connector.py

@@ -1145,7 +1145,7 @@ def save_kv_layer(self, layer_name: str, kv_layer: Tuple[torch.Tensor,
                       connector_metadata: MooncakeLayerwiseConnectorMetadata,
                       **kwargs) -> None:
         """MooncakeLayerwiseConnector does not save explicitly."""
-        if self.kv_role == 'kv_producer' and connector_metadata.request.keys():
+        if self.kv_role == 'kv_producer' and connector_metadata.requests.keys():
             if self.pd_head_ratio != 1:
                 if self.current_layer != 0:
                     self.completion_event.wait()