Change serialization of Job/Long Running Operations errors so they are more easily rendered/human readable

Currently `long_running_operations` stores errors encountered during failed Jobs (like during a merge or file upload) but these errors are serialized as [a Status](https://pkg.go.dev/google.golang.org/grpc/status).

This makes it more complicated to parse/render the error stored in the table. This requires a bit of work to change, it has yet to be scheduled.