Warn users about invalid markets

[kongzii]

There is a new endpoint, /market-invalid/; see https://labs-api.ai.gnosisdev.com/docs#/ for details.

Given market id, it returns boolean if the market is deemed invalid:

{
  "market_id": "0x303bf745ff66c457b7d8722a429824c6d3617c0c",
  "created_at": "2024-10-23T07:42:12.207835Z",
  "invalid": false
}

It's based on Omen rules, this is the prompt used for evaluation: https://github.com/gnosis/prediction-market-agent-tooling/blob/main/prediction_market_agent_tooling/tools/is_invalid.py#L22

(responses are cached forever, so it can be called as much as needed)