Fix KeyError: 'command' in MCP client by supporting nested config structure

[belltagy]

Description:
Bug Report
Environment:
OS: Windows 10
Python: 3.10
Package: huggingface_hub (MCP implementation)
Issue:
The MCP client fails to connect to stdio servers when the configuration uses a nested config structure in agent.json.
Current (broken) configuration structure:

{
    "servers": [
        {
            "type": "stdio",
            "config": {
                "command": "npx",
                "args": ["@playwright/mcp@latest"]
            }
        }
    ]
}

Workaround:
Flatten the configuration structure:

{
    "servers": [
        {
            "type": "stdio",
            "command": "npx",
            "args": ["@playwright/mcp@latest"]
        }
    ]
}

[caioriscala]

same here