[receiver/prometheusreceiver] Fix staleness issue for histograms and summaries

[gracewehner]

Description: Fixes bug where staleness NaN cannot be sent for histogram buckets and summary quantiles because these are not sent with the datapoint when it is marked stale, so components like the PRW exporter cannot set these metrics as stale. The actual values of these buckets and quantiles would be the stale NaN, but this sends the value as 0 instead because these need to be type uint64.

Link to tracking Issue: #8492

Testing: Tested with prometheus receiver -> OTLP exporter. Added test cases for otlp_metricfamily.go similar to the ones that already exist for histogram and quantiles, but instead with stale NaN values.

[Aneurysm9]

Please add a CHANGELOG.md entry. LGTM conceptually, just a couple minor questions/suggestions.

[dashpole]

Do we even need to set bucket counts? IIUC, we just needed the bounds to be able to manufacture stale bucket series with NaN values later.

[gracewehner]

That's true, we don't necessarily need the bucket counts to set the NaN values later. This would just also require a change in the PRW exporter for the line if index >= len(pt.BucketCounts()) {:

opentelemetry-collector-contrib/pkg/translator/prometheusremotewrite/helper.go

Lines 324 to 335 in fa86bb0

	for index, bound := range pt.ExplicitBounds() {
	if index >= len(pt.BucketCounts()) {
	break
	}
	cumulativeCount += pt.BucketCounts()[index]
	bucket := &prompb.Sample{
	Value: float64(cumulativeCount),
	Timestamp: time,
	}
	if pt.Flags().HasFlag(pdata.MetricDataPointFlagNoRecordedValue) {
	bucket.Value = math.Float64frombits(value.StaleNaN)
	}

[dashpole]

It can also be done as a follow-up. I wouldn't be surprised if many exporters don't handle that case correctly.