enhancement(metrics): ddsketch averages are calculated from histogram sum & count fields

[tony-resendiz]

Summary

when histograms are processed by the datadog metrics sink a ddsketch is built by interpolating values from the bucket boundaries. this causes some slight inaccuracy in the sketch average. this change sets the sketch average to the histogram's sum / count.

Vector configuration

[log_schema]
level_key = "status"
level = "info"

[api]
enabled = true
address = "0.0.0.0:8787"
playground = false

[sources.opentelemetry]
type = "opentelemetry"
grpc.address = "0.0.0.0:4317"
http.address = "0.0.0.0:4318"

[sinks.datadog_metrics_sink]
type = "datadog_metrics"
inputs = ["opentelemetry.metrics"]
default_api_key = "${DD_API_KEY}"
endpoint = "https://metrics.agent.datadoghq.com"

How did you test this PR?

built new vector binary and tested against the above config.

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

• Closes: ddsketch from histogram seems inaccurate #24365

Notes

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[tony-resendiz]

I have read the CLA Document and I hereby sign the CLA

[tony-resendiz]

Thank you for your submission, we really appreciate it. Like many open-source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution. You can sign the CLA by just posting a Pull Request Comment same as the below format.

I have read the CLA Document and I hereby sign the CLA

tresendiz seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.You can retrigger this bot by commenting recheck in this Pull Request. Posted by the CLA Assistant Lite bot.

sry tresendiz is my gh user for my company's gh. i linked that public ssh key to my tony-resendiz account but im not able to login/link that email and sign.