[APIServer] metrics use port the same as api_port

[xyxinyang]

Motivation

FD启动在线推理服务时需额外指定 metrics-port，不方便用户使用。

Modifications

设置metrics默认访问地址和服务端口一致，不指定metrics-port端口参数时，和服务端口一致

Usage or Command

python -m fastdeploy.entrypoints.openai.api_server \
       --model /root/paddlejob/models/ERNIE-4.5-0.3B-Paddle  \
       --gpu-memory-utilization 0.9 \
       --tensor-parallel-size 1 \
       --port 8280 \
       --engine-worker-queue-port 8285 \
       --cache-queue-port 8287 \
       --max-model-len 32768 \
       --max-num-seqs 32

Accuracy Tests

已有单测，单测覆盖率超过80%

Checklist

• Add at least a tag in the PR title.
  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
  • You can add new tags based on the PR content, but the semantics must be clear.
• Format your code, run pre-commit before commit.
• Add unit tests. Please write the reason in this PR if no unit tests.
• Provide accuracy results.
• If the current PR is submitting to the release branch, make sure the PR has been submitted to the develop branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

[paddle-bot]

Thanks for your contribution!