[Misc] update log level debug to warning when process port is used by (#24226)

Signed-off-by: rongfu.leng <rongfu.leng@daocloud.io>
Co-authored-by: Cyrus Leung <tlleungac@connect.ust.hk>

vllm/entrypoints/launcher.py

@@ -95,7 +95,7 @@ async def serve_http(app: FastAPI,
         port = uvicorn_kwargs["port"]
         process = find_process_using_port(port)
         if process is not None:
-            logger.debug(
+            logger.warning(
                 "port %s is used by process %s launched with command:\n%s",
                 port, process, " ".join(process.cmdline()))
         logger.info("Shutting down FastAPI HTTP server.")