[Bug] MCP settings shows no servers although user config APIs return enabled servers

### Short summary

After upgrading and restarting the GitHub Copilot app, **Settings > MCP servers** shows **"No servers configured"**, even though user-level MCP configuration is intact and the configured servers remain available to sessions.

This may be related to #2838, but this report includes a reproducible case on v1.1.10 where the bundled SDK can read and discover the servers successfully while the settings UI renders an empty list.

### Affected version or release

- GitHub Copilot app: 1.1.10
- Bundled Copilot CLI runtime: 1.0.80
- OS: Windows

### What happened?

The MCP settings page reports that no servers are configured.

Independent checks using the app's bundled SDK show:

- `mcp.config.list`: 5 user-configured servers
- `mcp.discover`: 5 servers
- Source: `user`
- Enabled: `true` for all 5

Each of the five configured MCP servers was also tested with a real, read-only tool call and responded successfully. The issue therefore appears limited to the settings UI's configured-server list rather than configuration loss or MCP runtime failure.

Server names, URLs, credentials, and tool response data are intentionally omitted.

### Steps to reproduce

1. Configure multiple user-level MCP servers for Copilot CLI / the GitHub Copilot app.
2. Confirm they are available and functioning.
3. Upgrade to GitHub Copilot app v1.1.10 and restart the app.
4. Open **Settings > MCP servers**.
5. Observe **"No servers configured"**.
6. Query the same runtime through the bundled SDK using `mcp.config.list` and `mcp.discover`.
7. Observe that both APIs still return the enabled user servers.

### Expected behavior

The MCP settings page should list the same user-configured servers returned by `mcp.config.list` / `mcp.discover`, including their enabled and connection state.

### Additional context

- The user-level MCP configuration file remains valid and unchanged.
- No configured servers are marked disabled.
- No enterprise MCP policy is filtering these servers.
- Restarting the app did not restore the list.
- The configured MCP tools remain usable from sessions despite the empty settings page.

Inizia da Settings > MCP servers e segui il modo in cui la UI ottiene l’elenco dei server configurati; confrontalo con le chiamate SDK incluse mcp.config.list e mcp.discover. Il lavoro è completato quando la pagina elenca gli stessi server utente abilitati e ne mostra lo stato di abilitazione e connessione, mentre le sessioni esistenti continuano a utilizzarli.

Scritto dal modello di indicizzazione a partire dal testo della issue.