[Port to 2.x]: feat: add per-user write byte statistics (#27547)

Port master-1.x commit https://github.com/influxdata/influxdb/commit/798e8bfc4e to main-2.x.

1.x records per-user write request bytes via the monitor statistics. 2.x has no equivalent; needs re-implementation on the http/metric event recorder / prometheus metrics, gated by a flag because of per-user label cardinality.