[Bugfix] Fix priority in multiprocessing engine (#9277)

vllm/engine/multiprocessing/engine.py

@@ -285,7 +285,8 @@ class MQLLMEngine:
                 params=request.params,
                 lora_request=request.lora_request,
                 trace_headers=request.trace_headers,
-                prompt_adapter_request=request.prompt_adapter_request)
+                prompt_adapter_request=request.prompt_adapter_request,
+                priority=request.priority)
 
             if self.log_requests:
                 logger.info("Added request %s.", request.request_id)