requestinfohandler: Restore missing log fields in SSHReceivePack

a497cfc8 replaced the v1 grpc-go-middleware Tags with the v2 logging.Fields, but this caused fields such as correlation_id and user_id to be dropped for calls such as SSHReceivePack. This occurred because the logger still uses the v1 StreamServerInterceptor and UnaryServerInterceptor, which extracts logging fields from a different context key than the one used by the v2 interceptors.

To restore these logging fields until the v2 middlewares are used, restore the v1 Tags. This means we have a bit of redundancy since the fields are stored for both v1 and v2 formats. However, once #5661 is complete, the v1 middleware and Tags can be dropped.