OTEL Prometheus Remote Write Exporter Metrics with Empty Labels

[atibdialpad]

Hi @robskillington ,
What is the expected behaviour in M3 if it receives OTEL PRW metrics with empty label values ?
Ex: version:""

Looking at https://github.com/m3db/m3/blob/master/scripts/docker-integration-tests/prometheus/test.sh#L128 it looks like M3 would drop these metrics and return a 400 ?

[atibdialpad]

and if there is a workaround to let these metrics pass through since Prometheus allows them.
https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels
"A label with an empty label value is considered equivalent to a label that does not exist."