otel/prometheus_exporter: disable otel_scope_info by default

[gouthamve]

The collector doesn't implement this yet and the metrics are not very useful.

See: open-telemetry/opentelemetry-collector-contrib#24248

• CHANGELOG.md updated
• Documentation added
• Tests updated
• Config converters updated

[tpaschalis]

LGTM, cc-ing @ptodev who worked on upgrading our OTel dependency this past week to merge.

[rfratto]

I'm not necessarily against the change, but I'm not sure if this is going against the compatibility spec.

The compatibility spec states:

Prometheus exporters SHOULD provide a configuration option to disable the otel_scope_info metric and otel_scope_ labels.

I took this to mean that the configuration option should exist, and should default to true. Did I misunderstand this line?

[clayton-cornell]

I took this to mean that the configuration option should exist, and should default to true. Did I misunderstand this line?

FWIW, I'd interpret this the same way.

[clayton-cornell]

Docs are OK as-is.

This doesn't account for the clarification of the default status.

[gouthamve]

Kicked off a discussion in OTEL land which led to this: open-telemetry/opentelemetry-specification#3657

Having the metrics switched on by default doesn't provide a lot of value and I think the spec will evolve to disable metrics unless there are attributes.

Should we go ahead and merge this? cc @rfratto