fix outdated env / VLLM_API_BASE

[fruworg]

Please describe the purpose of this pull request.
Fix for #2681 (comment)

How to test
docker compose up -d
curl -H http://localhost:8283/v1/models/ -s | jq

  {
    "model": "<vllm-model>",
    "model_endpoint_type": "openai",
    "model_endpoint": "http://vllm:8000/v1",
    "provider_name": "vllm",
    "provider_category": "base",
    "model_wrapper": "chatml",
    "context_window": 2048,
    "put_inner_thoughts_in_kwargs": true,
    "handle": "vllm/<vllm-model>",
    "temperature": 0.7,
    "max_tokens": null,
    "enable_reasoner": true,
    "reasoning_effort": null,
    "max_reasoning_tokens": 0,
    "frequency_penalty": null,
    "compatibility_type": null,
    "verbosity": null,
    "tier": null
  }

Have you tested this PR?
Yup.

Related issues or PRs
#2681 (comment)

Is your PR over 500 lines of code?
Nope.