Support lora metrics in vLLM

[Jeffwan]

🚀 Feature Description and Motivation

FYI

Use Case

No response

Proposed Solution

No response

[Jeffwan]

Problem 1: incorrect label names

{'model_name': 'meta-llama/Llama-2-7b-hf', 'running_lora_adapters': '', 'waiting_lora_adapters': '', 'max_lora': '1'}

_log_gauge_string doesn't need merge actually

[Jeffwan]

https://github.com/vllm-project/vllm/pull/11117 update the code to address it.