Track dropped trace metrics in client outcomes/reporting #1013
Description
Follow up on #997 by making dropped/rate-limited trace metrics visible in the SDK’s client outcomes reporting path where supported. This addresses the SHOULD-level dropped-metric outcome guidance in the trace metrics spec.
Scope from #997
No direct code extraction is needed from #997; this is a follow-up gap identified during spec review.
Details
Extend outcome tracking so metric drops (including rate-limited cases) are represented consistently with other data categories. The implementation should include tests that exercise at least one dropped path and verify the expected outcome/category accounting.