Update Sentry reporting further

[S7evinK]

#3305 made reporting errors a bit better, but there are still places in the code where we CaptureException in go routines, possibly still sending garbage to Sentry.
For reference: https://docs.sentry.io/platforms/go/usage/concurrency/

It may also make sense to check if we even should report said errors to sentry, as e.g. we should always be able json.Unmarshal things we sent to JetStream ourselves.