feat: add `traceContext` SQL commenter plugin
This restores the functionality lost in Prisma 7 / QC.
Previously QE would always append the `traceparent` comments to the SQL
queries when tracing was enabled, adding unnecessary overhead and
prepared statement hit misses (on MySQL; we solved the problem for
PostgreSQL back then by using `tokio_postgres`'s `query_typed`).
Conversely, `QueryInterpreter` in QC architecture doesn't implement
`traceparent` support at all, so users relying on that functionality
have reduced observability.
This PR makes use of the new SQL commenter plugin system to add an
opt-in mechanism for appending `traceparent` comments to SQL queries
only for those users who want it.