chore(mcp): update mcp server to use production URL

[reidbarber]

Closes #9462

Updates the MCP servers to use the production docs URLs.

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

Build the servers locally: yarn build:mcp.

Then run the servers locally:

{
  "mcpServers": {
    "React Aria": {
      "command": "node",
      "args": ["/Users/{your_path}/react-spectrum/packages/dev/mcp/react-aria/dist/react-aria/src/index.js"]
    },
    "React Spectrum (S2)": {
      "command": "node",
      "args": ["/Users/{your_path}/react-spectrum/packages/dev/mcp/s2/dist/s2/src/index.js"]
    }
  }
}

Make sure it fetches the latest docs pages and page content.

🧢 Your Project: