Fix Reset button to restore default API host instead of clearing

[Copilot]

Reset button in model configuration was clearing the API Host field. Now restores provider default.

Changes

• src/pages/Setting/Models.tsx: Modified handleDelete to restore item.apiHost from INIT_PROVODERS instead of empty string

// Before
return {
  apiKey: '',
  apiHost: '',  // ❌ Cleared field
  // ...
};

// After  
return {
  apiKey: '',
  apiHost: item.apiHost,  // ✅ Restores default (e.g., https://api.anthropic.com/v1/)
  // ...
};

Applies to all providers: Anthropic, OpenAI, Gemini, OpenRouter, Qwen, DeepSeek, etc.

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Feature Request] Reset clears API Host Setting instead of restoring default value</issue_title>
<issue_description>### Motivation

When a user clicks Reset on a model configuration, the API Host Setting field becomes empty. It should be automatically restored to the default API host for that provider (pre-filled), rather than blank.

Solution

No response

Alternatives

No response

Additional context

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Feature Request] Reset clears API Host Setting instead of restoring default value #1181

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[Pakchoioioi]

have tested it, this issue has been fixed.