Integer division causes loss of precision on trace span durations

[SpencerTorres]

The OTel exporter defaults to nanosecond precision, but Grafana requires that span durations be in milliseconds. This causes a lot of rows to be returned with a 0 duration, and spans that run under 1ms to be ruined in the trace visualization.

Broken:

Correct:

See in the correct result how the spans are correctly showing under 1ms