perf(language_server): transform Message to DiagnosticReport with one call (#14448)

The struct `MessageWithPosition` is not needed anymore. `oxc_linter` is sending `Message` and the server is storing `DiagnosticReport`. So we can save the transformation `Message -> MessageWithPositoin -> DiagnosticReport` and transform direct: `Message -> DiagnosticReport`.

Removed all relevant code and implemented `message_to_diagnostic_report`.

related https://github.com/oxc-project/backlog/issues/175

Author: Sysix