lsp: Add server-side tracing support (#15230)

This PR adds another row to the LSP log view: Server traces

![image](https://github.com/user-attachments/assets/e3f77944-45e0-4d04-92fd-aea212859e86)


[Traces](https://docs.rs/lsp-types/latest/lsp_types/notification/enum.LogTrace.html)
are intended for logging execution diagnostics, which is different from
`LogMessage` that we currently support.
When `Server trace` is selected, user can select the level of tracing
(`off`/`messages`/`verbose`) to their liking.

Release Notes:

- Added support for language server tracing to the LSP log view.