[Refactor] Remove legacy --stage-configs-path from the serve CLI (#5647)

Signed-off-by: zwhzzz0821 <2831474076@qq.com>

docs/user_guide/examples/online_serving/bagel.md

@@ -40,7 +40,7 @@ bash run_server_stage_cli.sh --stage 0
 bash run_server_stage_cli.sh --stage 1
 ```
 
-To use a custom deploy YAML (note: `--stage-configs-path` is deprecated in favor of `--deploy-config`):
+To use a custom deploy YAML:
 
 ```bash
 vllm serve ByteDance-Seed/BAGEL-7B-MoT --omni --port 8091 \