chore: Include litellm v readiness

[noahpodgurski]

What's new

• LiteLLM updated their readiness to not include the version anymore
• Re-include it in MLPA /health/readiness by calling public/model_hub/info
• Fix warnings, make tests more consistent

Before:

{
  "status": "connected",
  "mlpa_version": "1.0.12",
  "pg_server_dbs": {
    "postgres": "connected",
    "app_attest": "connected"
  },
  "litellm": {
    "status": "healthy",
    "db": "connected"
  }
}

After:

{
  "status": "connected",
  "mlpa_version": "1.0.12",
  "pg_server_dbs": {
    "postgres": "connected",
    "app_attest": "connected"
  },
  "litellm": {
    "litellm_version": "1.84.4",
    "status": "healthy",
    "db": "connected"
  }
}

https://mozilla-hub.atlassian.net/browse/AIPLAT-1035