Introduce OTel SPI Metrics

[mhlidd]

What Does This Do

With the end goal to track which SPIs are used frequently with dd-trace-java, this PR introduces the skeleton needed to report this metrics. Notable tags are spi_class and source.

Motivation

Additional Notes

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Jira ticket: [PROJ-IDENT]

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Enqueue SPI detections before draining

In any runtime where OTel SPI providers are present, this metric will still never be emitted: I checked repo-wide (rg recordSpiDetected) and the only callers are the new tests, so the telemetry action drains an always-empty queue. Please wire the SPI discovery/loading path to call this method before enabling the periodic action.

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