influx2otel: error on field named "count"

[seankhliao]

Running the influxdbreceiver in the opentelemetry collector,
we see metrics submission fail with "failed to append to the batch".
Bisecting our metrics output, we find that it errors on lines like:

foo count=2i 

Renaming count to something else allows submission to work, but this is a third party application that we can't easily change.

[seankhliao]

I found a related (same?) issue influxdata/telegraf#14371

I think it's from https://github.com/influxdata/influxdb-observability/blob/main/influx2otel/metrics_telegraf_prometheus_v1.go#L52-L58 where it assumes it's a histogram but not all fields are present