[ty] Avoid panicking when there are multiple workspaces (#18151)
## Summary
This PR updates the language server to avoid panicking when there are
multiple workspace folders passed during initialization. The server
currently picks up the first workspace folder and provides a warning and
a log message.
## Test Plan
<img width="1724" alt="Screenshot 2025-05-17 at 11 43 09"
src="https://github.com/user-attachments/assets/1a7ddbc3-198d-4191-a28f-9b69321e8f99"
/>
