Investigate registering `WithUnhandledExceptionHandler` on language server startup

Omnisharp allow registering a generic unhandled exception handler using `server.WithUnhandledExceptionHandler(...)`. Might be worth exploring this for:
* Raising telemetry about failures
* Showing a more user-friendly dialog along with a "report issue" button capturing any relevant diagnostics.

Begin at the language server startup entry point and review how OmniSharp's server.WithUnhandledExceptionHandler(...) could be registered. Assess the two proposed outcomes—failure telemetry and a user-friendly dialog with a report-issue button capturing relevant diagnostics—and document the investigation's result.

Written by the indexing model from the issue text.