PeriodicMetricReader emits otel.sdk.metric_reader.collection.duration unconditionally, bypassing the experimental self-observability opt-in

[cijothomas]

PeriodicMetricReader / MetricReaderInstrumentation records otel.sdk.metric_reader.collection.duration unconditionally whenever a real MeterProvider is available — it never checks otel.experimental.sdk.telemetry.version (OTEL_EXPERIMENTAL_SDK_TELEMETRY_VERSION).

This is inconsistent with the rest of the self-observability suite: TracerProviderConfiguration and LoggerProviderConfiguration both call InternalTelemetryConfiguration.getVersion(config) before enabling span/log processor self-observability, and OtlpConfigUtil does the same for OTLP exporter self-observability. There's no equivalent check in the metric reader path.

Repro: run any service with metrics enabled via the Java agent/autoconfigure, without setting OTEL_EXPERIMENTAL_SDK_TELEMETRY_VERSION — otel.sdk.metric_reader.collection.duration still shows up, while span/log/exporter self-observability correctly stays off.

[cijothomas]

Found while working on open-telemetry/opentelemetry-demo#3621 where couple of services (java agent based) emitted this metric even though I missed to opt-in to it. Not sure if this is significant enough to change now, more like FYI.