### Check for existing issues

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

### What happened?

## `vector_store_ids` Automatically Injected When Editing a Model via UI, Breaking Gemini Embedding Models

### Description

When editing an existing model configuration through the LiteLLM UI (or proxy config), the parameter `vector_store_ids` is automatically added to the model's `litellm_params`. This causes a `400 Bad Request` error for Gemini embedding models (e.g., `gemini-embedding-001`), since Gemini does not recognize this field.

### Expected Behavior

Only the explicitly configured parameters should be present in `litellm_params`. Editing a model should not silently inject additional parameters like `vector_store_ids`.

### Actual Behavior

After editing, `vector_store_ids` is automatically added to the model's `litellm_params`, resulting in the following error:

``` litellm.BadRequestError: GeminiException BadRequestError - { "error": { "code": 400, "message": "Invalid JSON payload received. Unknown name \"vector_store_ids\" at 'requests[0]': Cannot find field.", "status": "INVALID_ARGUMENT", "details": [ { …