### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

When i want to add fields to the `Model Info` json of a model they are discarded.

E.g. i want to add a "max_input_tokens" to an existing model:

<img width="796" height="275" alt="Image" src="https://github.com/user-attachments/assets/ae25d5ca-4484-4578-96f1-7850fadcecab" />

But even after saving the setting successfully the model reports this raw json:

```json { "model_name": "[CONTRACTED] Nebius: Kimi-K2.5", "litellm_params": { "input_cost_per_token": "5e-07", "output_cost_per_token": "2.5e-06", "custom_llm_provider": "nebius", "litellm_credential_name": "Nebius", "use_in_pass_through": false, "use_litellm_proxy": false, "merge_reasoning_content_in_choices": false, "model": "moonshotai/Kimi-K2.5", "tags": [], "guardrails": [] }, "model_info": { "id": "2da0f0bf-7a18-4b32-b0ea-da0fbb1bb53e", "db_model": true, "mode": "chat", "access_groups": [], "direct_access": true, "access_via_team_ids": [ "ai-self-service" ], "input_cost_per_token": 5e-7, "output_…